This reverts commit ab707aca.

# Description
Currently the benchmarks test prints a scary warning message, even when it passes, that a benchmark is being run with asserts enabled.

Normally we don't want developers to do this, because the performance of code with asserts is not characteristic of what end-users will experience. However, we need to unit-test benchmarkWidgets, so I've added a contraindicated option to suppress the warning for the test.

# Related Issues
25049 (comment)

Revert "Add currentSystemFrameTimeStamp to SchedulerBinding (#33886)"

This reverts commit 61b83d32.

Convert scheduling to use `scheduleMicrotask` instead of `Timer.run`

* Deprecates `BinaryMessages` in favor of a default instance of `BinaryMessenger`, called `defaultBinaryMessenger`
* Platform channels use the `defaultBinaryMessenger` for their binaryMessenger default argument.

git log --oneline --no-merges f4951df193a7966f9ed4da43d555eee0913d84d1..a48cd16e077778a7aa5908e4faa4da07714260f2
a48cd16e0 Update a11y word forward/back enum names (https://github.com/flutter/engine/pull/8073)
b5f59ed89 Delay the vsync callback till the frame start time specified by embedder. (https://github.com/flutter/engine/pull/8072)
7426305f5 Mark const extern (https://github.com/flutter/engine/pull/8077)
d3f6d7a21 only partial rule revert (https://github.com/flutter/engine/pull/8078)
d71bfe58d Only build a full Dart SDK when building for the host system (https://github.com/flutter/engine/pull/8071)
de90dbff7 Refactor web configuration/ Add dartdevc (https://github.com/flutter/engine/pull/7978)
ff46dd38f Roll src/third_party/skia 4c1ea43a79b5..88b8d1124b72 (8 commits) (https://github.com/flutter/engine/pull/8070)
80c6dd286 Roll src/third_party/skia 692122e3ef23..4c1ea43a79b5 (3 commits) (https://github.com/flutter/engine/pull/8069)
68ed654ea Roll src/third_party/skia 3c957d575c58..692122e3ef23 (6 commits) (https://github.com/flutter/engine/pull/8067)
ca0bac4fb Revert "add signal to pointer kinds" (https://github.com/flutter/engine/pull/8066)
3fb627f2c add signal to pointer kinds (https://github.com/flutter/engine/pull/8065)
5a06afa2a Roll src/third_party/skia 801a9c16d81e..3c957d575c58 (19 commits) (https://github.com/flutter/engine/pull/8063)
a93d99db9 A11y callback (https://github.com/flutter/engine/pull/8005)
3661d5e43 Re-land "Buffer lifecycle in WindowData" (https://github.com/flutter/engine/pull/8032)
471a2c89a Send scroll events from the macOS shell (https://github.com/flutter/engine/pull/8056)
2fe9c9b5f Roll src/third_party/skia 72542816cadb..801a9c16d81e (46 commits) (https://github.com/flutter/engine/pull/8060)
3335764ae Skip skp files in license check (https://github.com/flutter/engine/pull/8050)
7f16789b2 Remove redundant thread checker in FML. (https://github.com/flutter/engine/pull/8053)
840c5233a Correct URL for Cirrus CI build status badge (https://github.com/flutter/engine/pull/8054)
57c120a29 remove extra source files (https://github.com/flutter/engine/pull/8052)
4773375c6 Used named conditionals for platform specific dependencies and suppress Android and Windows hooks on Mac. (https://github.com/flutter/engine/pull/8051)
70a18b515 Add clang static analysis support to gn wrapper (https://github.com/flutter/engine/pull/8047)
b30f9897b Improve elevation bounds for physical shape layers (https://github.com/flutter/engine/pull/8044)
e37bd27b4 Fix weak pointer use violations in shell and platform view. (https://github.com/flutter/engine/pull/8046)
dd80fc9ff Add engine support for scrollwheel events (https://github.com/flutter/engine/pull/7494)

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

* Upgrade everything except matcher.
* Roll matcher (and test)
* Adjust tests that depend on flutter:test directly to depend on a shim
* Require use of package:test shim and remove other references to package:test

The verbosity change is to help track down timeouts that currently look like:

```
C:\Windows\Temp\flutter sdk>call bin\flutter.bat config --no-analytics
Checking Dart SDK version...
Downloading Dart SDK from Flutter engine c5a63d28bf3735569c8187753bc490d8351a8363...
Unzipping Dart SDK...
Updating flutter tool...
```

* always schedule first frame when creating ticker, regardless of phase or frame

* Lock events during runApp's warm up frame

* move to scheduler binding

* let the one scheduleWarmUpFrame api always lock

* tweak test

* Add more checks to scheduleWarmUpFrame

* review

* add test

...instead of the engine.

* enable lint prefer_foreach

* fix tests

This splits the frame pipeline into two, beginFrame and drawFrame.

As part of making this change I added some debugging hooks that helped
debug the issues that came up:

 * I added debugPrintScheduleFrameStacks which prints a stack whenever
   a frame is actually scheduled, so you can see why frames are being
   scheduled.

 * I added some toString output to EditableText and RawKeyboardListener.

 * I added a scheduler_tester.dart library for scheduler library tests.

 * I changed the test framework to flush microtasks before pumping.

 * Some asserts that had the old string literal form were replaced by
   asserts with messages.

I also fixed a few subtle bugs that this uncovered:

 * setState() now calls `ensureVisualUpdate`, rather than
   `scheduleFrame`. This means that calling it from an
   AnimationController callback does not actually schedule an extra
   redundant frame as it used to.

 * I corrected some documentation.

Also, fix some minor bugs with SynchronousFuture.

* MultiTapGestureRecognizer previously would assert if there was no
   competition.
 * GestureArenaTeam would always select the first recongizer as the
   winner even if a later recognizer actually accepted the pointer
   sequence.
 * debugPrintStack would fail a type check if maxFrames was non-null.
 * FractionalOffset.lerp would throw a null-pointer exception if its
   second argument was null.

Also, add a number of tests for previously untested lines of code.

Previously, the ticker would not stop when it was muted because it thought it
was already not ticking.

Also, fix the bug where apps would assert when you change the time dilation.
Use that mechanism to fix the animation controller tests.

The old names were getting silly and started stepping on valuable namespace.

The new names are consistent and clear.

We're getting back to the point where we have a bunch of foundation APIs
and it's getting confusing having them mixed with services/.

This test is no longer disabled.

Fixes #2827

Well, all the easy ones, anyway.

For some reason `// ignore:` isn't working for me so I've disabled
lints that need that. Also disabled those that require a ton of work
(which I'm doing, but not in this PR, to keep it reviewable).

This adds:
- avoid_init_to_null
- library_names
- package_api_docs
- package_names
- package_prefixed_library_names
- prefer_is_not_empty
- sort_constructors_first
- sort_unnamed_constructors_first
- unnecessary_getters_setters