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 c0af77bf.

Use PRODUCT_BUNDLE_IDENTIFIER from buildSettings to find correct bundle id on iOS when using flavors (#42964)

So we can test SkSL precompile using the command line tools.
See https://github.com/flutter/engine/pull/12412.

Fixes various Flutter framework test failures when bytecode is enabled.

* add missing trailing commas

* add more missing trailing commas

* add more and more missing trailing commas

- Makes build_macos.dart handle the case where there is only one Xcode
  project in the macos/ directory, but it's not called Runner.xcodeproj
- Makes getInfo throw a tool exit when trying to get project info and it
  can't find a project, since that is a configuration error by the user
  rather than a tool bug.

Avoids unnecessarily breaking projects that have another .xcodeproj in
their macos/ directory, which worked until the addition of the getInfo
call.

We were using the `defaults` command-line utility to parse
Plist files, but it was never supported by Apple, and it
appears that in an upcoming OS release, it will be less likely
to work:

> WARNING: The defaults command will be changed in an upcoming
> major release to only operate on preferences domains. General
> plist manipulation utilities will be folded into a different
> command-line program.

Fixes https://github.com/flutter/flutter/issues/37701

Fixes https://github.com/flutter/flutter/issues/36789
Fixes https://github.com/flutter/flutter/issues/37000

https://github.com/flutter/flutter/issues/36524
https://github.com/flutter/flutter/issues/24600