* [web][upstream] Fix debugPrintStack for web platform

Fixes: https://github.com/flutter/flutter/issues/37488

* use sentence case in error message titles

* add a test

Make FlutterError objects more structured so they can be displayed better in debugging tools such as Dart DevTools.

* add trailing commas on list/map/parameters

* add trailing commas on Invocation with nb of arg>1

* add commas for widget containing widgets

* add trailing commas if instantiation contains trailing comma

* revert bad change

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

* Upgrade everything except matcher.
* Roll matcher (and test)
* Adjust tests that depend on flutter:test directly to depend on a shim
* Require use of package:test shim and remove other references to package:test

Fixes https://github.com/flutter/flutter/issues/10695

* MultiTapGestureRecognizer previously would assert if there was no
   competition.
 * GestureArenaTeam would always select the first recongizer as the
   winner even if a later recognizer actually accepted the pointer
   sequence.
 * debugPrintStack would fail a type check if maxFrames was non-null.
 * FractionalOffset.lerp would throw a null-pointer exception if its
   second argument was null.

Also, add a number of tests for previously untested lines of code.