This also involves switching from Core JIT to App JIT snapshot, and replacing per-isolate VM snapshot with the shared VM snapshot.

For now there is no separate update bundle file, as the generated update gets packaged directly into the APK for testing purposes.

This changes the compiler output for gradle to be less verbose and more easily read.

This only applies to compilation error messages: other gradle messages will continue to print as before.

It also fixes a small problem with the performance measurement printing (see that "7.1s" on it's own line in the original?) so that if something is expected to have multiple lines of output, it prints an initial line, and a "Done" line with the elapsed time, so that it's possible to know what the time applies to.

It also updates the spinner to be fancier, at least on platforms other than Windows (which is missing a lot of symbols in its console font).

Addresses #17307

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

This patch eliminates the --preview-dart-2/--no-preview-dart-2 flag,
hardcoding all uses to true. It also defaults all previewDart2 method
parameters to true, where they hadn't yet been.

A series of subsequent patches will eliminate all previewDart2
parameters and the associated code from within the codebase.

* Revert "iOS Dialog blur, brightness, and layout (#18381)"

This reverts commit 21bc9f1b.

* Revert "Flutter tool support for dynamic code. (#20543)"

This reverts commit 25ba90aa.

- Check memory usage in release builds, not profile.
- Use multiple runs and average the results.

This reverts commit cacd291c.

* Revert "Add pub cache, artifacts, pkgs to Cirrus cache (#20080)"

This reverts commit 07e93b38.

* Revert "Reduce noise on the memory benchmarks (#19630)"

This reverts commit 8eb5cb7d.

- Check memory usage in release builds, not profile.
- Use multiple runs and average the results.

Disallow calling stop() or cancel() multiple times. This means that
when you use startProgress you have to more carefully think about what
exactly is going on.

Properly cancel startProgress in non-ANSI situations, so that
back-to-back startProgress calls all render to the console.

This reverts commit 0636c6fe.

Disallow calling stop() or cancel() multiple times. This means that
when you use startProgress you have to more carefully think about what
exactly is going on.

Properly cancel startProgress in non-ANSI situations, so that
back-to-back startProgress calls all render to the console.

With a fix of a path being printed relative instead of absolute.

This reverts commit 57d78cc7.

Add flutter tool support for creating app-specific VM snapshots.

fuchsia_tester.dart still assumes Dart 1. Previously, it ran tests directly
from source, flutter_platform.dart automatically runs a kernel compile when
operating in Dart 2 mode, but this assumes a functional Dart SDK is available
in the artifacts directly, and fuchsia_tester.dart mocks out the artifacts
directory with an empty temp dir.

Remaining work is:
1. Get the frontend server building as a dependency on Fuchsia.
2. Patch fuchsia_tester.dart to use a valid Dart SDK and frontend server.

This also reverts migration to Dart 2 typedef syntax.

This reverts commit 6c56bb24. (#18362)
This reverts commit 3daebd05. (#18316)

* It's time to #deleteDart1 (#18293)

Eliminates support for Dart 1 in flutter_tools, and drops our Dart 1
benchmarks. All commands now run in Dart 1 mode only.

Eliminates --preview-dart-2 / --no-preview-dart-2 support.

* Fix indentation, remove no longer necessary .toList()

* Only push udpated kernel if >0 invalidated srcs

Several benchmarks started failing during kernel compile:
1. Timeouts:
   * commands_test
   * hot_mode_dev_cycle__benchmark
   * run_machine_concurrent_hot_reload
   * service_extensions_test

2. Kernel compiler crash:
   * hot_mode_dev_cycle_linux__benchmark
   * routing_test

3. Unexpected termination:
   * hot_mode_dev_cycle_win__benchmark

This reverts commit ed63e708.

Eliminates support for Dart 1 in flutter_tools, and drops our Dart 1
benchmarks. All commands now run in Dart 1 mode only.

Eliminates --preview-dart-2 / --no-preview-dart-2 support.

The change in 8b8d368d has only renamed the flag in a subset of the
places.

Uses the `version` property from the `pubspec.yaml` file to set the corresponding fields in the `local.properties` file respectively in the `Generated.xcconfig` file.

The `--build-name` and `--build-number` options have changed. Now they trump the `version` property from the `pubspec.yaml` file.

If the `version` property is not set and the  `--build-name` and `--build-number` options are not provided, the build command will not change the `local.properties` / `Generated.xcconfig` file.

This is follow-up to https://github.com/flutter/flutter/pull/17682 to fix dart1 tests.

Fixes #16832

* Search for a suitable ARM sysroot instead of hardcoding it;
* Add facility to explain why NDK was not found;

add --buildNumber and --buildName to flutter build like
flutter build apk --buildNumber=42 --buildName=1.0.42