Migrate tests in flutter/flutter. Once the tests here and in `*_customer_testing` are migrated, the default value of the migration flag will be changed from false to true, making the rounding hack disabled by default.
Updated the localization tests so that they'll DTRT when useMaterial3:true becomes the default for ThemeData. In a few cases there are M2 and M3 tests now, to check features that are significantly different in Material3, notably the double ring for the 24 hour input dial.
| Material 2 | Material 3|
|---------|---------|
| <img width="250" alt="Screenshot 2023-06-08 at 10 47 37 AM" src="https://github.com/flutter/flutter/assets/1377460/6ca95e22-b3f1-4f6b-9e39-79c888ba58f1"> | <img width="257" alt="Screenshot 2023-06-08 at 10 47 13 AM" src="https://github.com/flutter/flutter/assets/1377460/19b685bf-c812-4c87-baed-70fa56efaad8"> |
In M3, most aspects of the ideographic text styles are the same as for alphabetic styles, so there are some tweaks here to account for that.
* 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
