Revert "flutter_tools: Remove unused //ignore comments; change flutter-specific ones to "ignore_for_flutter" (#45917)" (#46999)

This reverts commit f2859201.

It broke forbidden_imports_test, which uses a custom ignore directive.

flutter_tools: Remove unused //ignore comments; change flutter-specific ones to "ignore_for_flutter" (#45917)

* Make golden test timeout longer, some tests are flaky if the timeout is too short

* Enable some golden tests for web

* Update project.pbxproj files to say Flutter rather than Chromium

Also, the templates now have an empty organization so that we don't cause people to give their apps a Flutter copyright.

* Update the copyright notice checker to require a standard notice on all files

* Update copyrights on Dart files. (This was a mechanical commit.)

* Fix weird license headers on Dart files that deviate from our conventions; relicense Shrine.

Some were already marked "The Flutter Authors", not clear why. Their
dates have been normalized. Some were missing the blank line after the
license. Some were randomly different in trivial ways for no apparent
reason (e.g. missing the trailing period).

* Clean up the copyrights in non-Dart files. (Manual edits.)

Also, make sure templates don't have copyrights.

* Fix some more ORGANIZATIONNAMEs

No code changes, just comments: I spell-checked all the comments in the repo.

* implicit-casts:false on flutter_tools/lib

* address review comments

* use castStringKeyedMap

* introduce {bool,string,strings}Arg

* fix ci

This reverts commit 0dc5ea4a.

Fixes various Flutter framework test failures when bytecode is enabled.

Applying our style guide:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#have-good-hygiene-when-using-temporary-directories

Bytecode generation will otherwise omit assert code, causing --enable-asserts to have no effect in the VM.

Spawn no more than 1 iframe in web tests. Using multiple iframes in DDK mode times out tests. Also set concurrency to 1 to guarantee that the test runner does not even attempt to parallelize tests. (#40630)

Spawn no more than 1 iframe in web tests. Using multiple iframes in DDK mode times out tests. Also set concurrency to 1 to guarantee that the test runner does not even attempt to parallelize tests.

An optimization to the coverage collection speed was added in #30811. This commit further expands on it to parameterize the CoverageCollector with a custom predicate, allowing internal use cases to filter the RPC calls to the Dart VM based on scripts of interest to coverage collection.

This is necessary for those who wish to comply with static analysis like
`strict-raw-types: true`, which includes generated code within their package.

* more ui-as-code

* address review comments

* Make it possible to override the FLUTTER_TEST env variable without unsetting it.

* Switch to using platform instead of Platform.

* Document the bindings, and introduce tests that initialize multiple WidgetsBindings with different environments.

* Add tests for the flutter platform test.

* Add license headers

* Fix lints

* Remove trailing whitespace

* Respond to Jonahs comments

* Respond to Ians comments

* Mock out the HttpServer in flutter_platform_test

* Mock out the HttpServer in flutter_platform_test

* Explain why we mock out the HttpServer in flutter_platform_test