Provide a flag for controlling the dart2js optimization level when building for web targets (#101945)

Co-authored-by: Christopher Fujino <christopherfujino@gmail.com>

* warn when doctor takes long

Fixes #86590

This changes the default build architectures for Flutter macOS apps to
x86_64 and arm64. Previously, we manually excluded arm64 builds via the
EXCLUDE_ARCHS Xcode setting in Flutter's generated xcconfig file. This
eliminates setting EXCLUDE_ARCHS during the build and updates the
default architectures in the tool and in the macos_assemble.sh wrapper.

Issue: https://github.com/flutter/flutter/issues/97681
Umbrella issue: https://github.com/flutter/flutter/issues/60113

* Fixed order dependency and removed no-shuffle-tag in build_ios_framework_test.dart

* Removed trailing spaces in build_ios_framework_test.dart

* Removed unnecessary formatting

This reverts commit ac3c4435.

* Update flutter_tools to look for new VM service message

The Dart SDK will soon move away from the current Observatory message:

"Observatory listening on ..."

To a new message that no longer references Observatory:

"Dart VM Service listening on ..."

This change updates all tests with mocks to check for the new message
and also adds support for the new message in ProtocolDiscovery.

See https://github.com/dart-lang/sdk/issues/46756

* Fix some parsing locations

* Fix analysis failures

* Update message

* Remove extra comment

* Update message

* Add globals prefix