* Switch iOS gen_snapshot from multi-arch binary to multiple binaries

* Make snapshotterPath mutable

This reverts commit 58092195.

* Remove multi-arch check in iOS builds

* Manual roll of https://github.com/flutter/engine/pull/10010

Slight cleanup of file locations in flutter_tools
to make it easier to see which files are responsible
for data reporting.

* more ui-as-code

* address review comments

Android now exclusively uses ELF shared libraries, and
iOS uses assembly.

AOT compiled code is now packaged as an ELF library for Android targets.
By default gen_snapshot's output contains debug symbols.  The symbols could
be stripped as a separate step, but that requires NDK tools that the user
may not have available.

This change passes a gen_snapshot flag that omits the symbols, and it filters
out a warning printed when that flag is used.

* Gradle generates ELF shared libraries instead of AOT snapshots.
* `flutter build apk/appbundle` supports multiple `--target-platform` and defaults to `android-arm` and `android-arm64`.
* `flutter build apk` now has a flag called `--split-per-abi`.

Revert "Generate ELF shared libraries and allow multi-abi libs in APKs and App bundles (#33696)" (#34121)

* Gradle generates ELF shared libraries instead of AOT snapshots.
* `flutter build apk/appbundle` supports multiple `--target-platform` and defaults to `android-arm` and `android-arm64`.
*  `flutter build apk` now has a flag called `--split-per-abi`.

Use Dart's new direct ELF generator to package AOT blobs as shared libraries in Android APKs (#33611)

This is a replacement for the old implementation of --build-shared-library
that emits an AOT assembly snapshot and feeds it to the Android NDK toolchain.

Splits Xcode validation out of the iOS validator and into a stand-alone
validator, and groups the CocoaPods validator with that top-level
validator instead of the iOS validator. iOS now validates only the
iOS-specific tools (e.g., ideviceinstaller).

Reorganizes many of the associated clases so that those that are used by
both macOS and iOS live in macos/ rather than ios/. Moves some
validators to their own files as part of the restructuring.

This is the macOS portion of #31368

This is the correct metric to report for compilation time benchmarks rather
than RunTime. Rename the 'gen_snapshot' value to merely 'snapshot' for
backwards compatibility and overall simplicity.

This change simplifies Dart's benchmarking of Flutter by making it easier to
adopt --report-timings (made for Dart to use), which makes the benchmarks
much more robust.

* Support release/debug flavors of flutter_patched_sdk

* Use [anyNamed] instead of [any] for mocking named arguments

* Fix use of local engine in release mode

This flag makes flutter build aot report timings for substeps (e.g.
frontend compilation and gen_snapshot) in a machine readable form.

This command line argument has already been removed in the main
Dart repository, so building flutter with the latest dart fails.

This time, also update the tests to avoid the checks for a package
path on snapshot generation.

This reverts commit 1c021506.

The pre-commit tests never actually ran, so it looked green when it wasn't. This breaks 16 tests that depend on the argument existing, even though it isn't actually used.

This command line argument has already been removed in the main
Dart repository, so building flutter with the latest dart fails.