* Create a main alias for master channel.
To slowly migrate away from master branch in the flutter repository we
created a main branch that is mirroring master branch. This PR is also
adding a channel alias that will allow to use master/main interchangeably.
Bug: https://github.com/flutter/flutter/issues/95041
* Fix channel tests.
* Remove additional space.
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
* 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
...because otherwise, processes that think they're manipulating your
filesystem will be doing crazy things the test is ignoring, leading to
(at best) failures and (at worst) flakes or disk corruption.
