Fixes https://github.com/flutter/flutter/issues/117245

Relands #126086, which was reverted by #126569.

Reverts flutter/flutter#126086.

This PR changed the interfaces of some classes, namely `AndroidSdk`, and deleted a global.

These classes had custom overrides in g3 that were not updated with a g3fix, so this PR has broken tests. See https://b.corp.google.com/issues/281945232 (non-public link)

This is the first step in unifying Java-finding logic across the tool. If curious, see #126029 for an example of what all the changes will probably entail.

Moves java-related functionality like `AndroidSdk.findJavaHome` to a new class, `Java`.

See tracking issue https://github.com/flutter/flutter/issues/126126 for more.

https://github.com/flutter/flutter/issues/120408

Revert "[flutter_tools] Remove sound null safety flag (#123031)"

[flutter_tools] Remove sound null safety flag #2

This reverts commit 7c3088cf.

[flutter_tools] Remove sound null safety flag

* update flutter build command

* update tests

* fix analyze suggestions

* Migrate packages/flutter_tools/test/commands.shard/permeable

* Fix upgrade_test

* Chris's comments

This reverts commit 8b6baae4.

Our current top crasher is an unclear error when ProcessManager fails to resolve an executable path. To fix this, we'd like to being adjusting the process resolution logic and adding more instrumentation to track failures. In order to begin the process, the ProcessManager has been folded back into the flutter tool

* opt out the flutter tool

* oops EOF

* fix import

* Update tool_backend.dart

* Update daemon_client.dart

* fix more

This reverts commit 8e73bab9.

Enable tree-shake-icons by default for non-web targets. Make missing fonts a status print

Ensure iOS and android builds can be correctly cached. Use the performance-measurement-file to verify that all targets were skipped on the second invocation. This is only run on the flutter_gallery build.

Revert "[flutter_tools] default tree-shake-icons to enabled and improve performance (#54923)" (#55413)

This reverts commit 0b93a921.