Revert "[flutter_tools] separate target platform, host platform, and architecutre (#60119)" (#60147)

This reverts commit 30d97d89.

Update all versions, specifically file which fixes some bugs that caused tests to fail if run in different orders:

- systemTemp directories created by MemoryFileSystem will allot names based on the file system instance instead of globally.
- MemoryFile.readAsLines()/readAsLinesSync() no longer treat a final newline in the file as the start of a new, empty line.
- RecordingFile.readAsLine()/readAsLinesSync() now always record a final newline.

Use Dart's characters package to fix user-facing grapheme cluster bugs.

separate target platform, host platform, and architecture

* fix test compiler test
* fix project test
* fix flutter_platform_test
* fix cocoapods test

* Make upscaling images opt-in

This is a PR addressing #57226 - Proposal: New UI for Licenses Page.

This PR replaces the previous single panel license page with one that uses a master/detail flow (MDFlow) to display packages and their respective licenses.

The License Page API remains unchanged. The logic for processing the license data is kept largely the same. This PR changes how the licenses are displayed, by introducing a responsive UI using the master/detail UI pattern. For now I am calling it Master Detail Flow, or MDFlow.

MDFlow manifests as two layouts depending on the screen size. On small and medium displays, as determined by the breakpoints given by the Material Design Spec, MDFlow utilises a nested layout. On large displays, MDFlow uses a two panel (lateral) layout. MDFlow is implemented in this PR using a Navigator for the nested layout, and a Stack for the lateral layout. The master and detail views are built using builders. For the interactive component, detail pages are requested from the master view using a proxy obtained by a widget lookup on the build context; MasterDetailFlow.of(context).

This reverts commit fe15d1e7.

Remove Linux shell window_configuration.cc/.h

It was a temporary solution while the shell was changing.

When `retainPriorEvents` is passed as true, the current behavior still limits timeline events to the timestamp after `traceEvents` is called. This can cause startup events to be missing.

This fixes it by passing null to `stopTracingAndDownloadTimeline` for the start and end time.

Related: #58430

* [flutter_tools] track null safety usage

* Update flutter_command_test.dart

* cleanups

Fixes several tests that were failing under tester. Minor style cleanups otherwise

The test needs to look up HOME, but one wasn't provided. This would end up using the real home directory, crashing on windows