This optimization resulted in app still running with old kernel file.
Fixes another source of https://github.com/flutter/flutter/issues/16604

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

Dart 1 is no longer supported in Flutter.

Script snapshots were only every used in Dart 1 mode, which is no longer
supported.

It was causing problems rolling Flutter into Fuchsia

* re-enable lint unnecessary_const

* remove trailling whitespaces

* remove unnecessary const (after merge)

* Remove uses of deprecated constants
* Change int.parse to int.tryParse where appropriate

This reverts commit cc1cf13e.

* adjust declared types to work with dart 2 typing at runtime

* review comments

* update packages/flutter_tools/lib/src/ios/simulators.dart

This is an attempt to reland #18488 with less breakage on macOS.

This reverts commit 77508722.

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.

* Patch to fix builds with custom targets on iOS simulator. #16787

* Fix for unused import.

* Code review changes applied.

Previously, Flutter did not support iOS devices with armv7 or armv7s
CPUs. We now support these devices. This eliminates the previous
hardcoded checks that prevented running on simulators of older devices.

We maintain the existing restriction on running on watchOS or tvOS
simulators.

The new values are not ready for use yet inside Google

* Roll engine to e976be13c51448f89107d082ec81e2b6731671fa

* move away from deprecated constants

* add logic to parse 11.3 sim runtime major version

* add null aware and bump group number

* add comment describing version