[flutter_tools] disable source maps by default for release builds, enable for run and with command line arg (#67331)

Disables source map production by default for build web. For web builds performed as a part of flutter run --release, enable the source maps, or allow force enabling with --source-maps command line flag.

fixes #67328

[null-safety] add integration tests for sound null safety modes, add support for sound null safety in dart2js (#67171)

Add integration tests to verify that ddc and dart2js can be built and run in sound mode. Updates dart2js compilation to insert a language version comment into the generated entrypoint if necessary.

dart-lang/sdk#42253

The main.dart.js bypass is not needed now that we have skipWaiting. Additionally optimize the fetch handler so that resources not in the cache skip the service worker altogether.

Fixes #66068

If a new service worker is installed, automatically update this behind the scenes. Immediately after a page refresh, the new worker and cache will be available, though the main.dart.js and others will be available sooner due to the cache busting URLS

Generates version.json in web directory of project. version.json can be used in the future version of package_info which will support web. version.json has the following keys : app_name, version and build_number. This file is generated every time a user runs or builds the project.
Co-authored-by: Jonah Williams <jonahwilliams@google.com>

Fix run release/profile modes generating a full service worker.

[flutter_tools] adjust index.html caching and insert cache busting URL in to main.dart.js/sw request (#64976)

Attempt to bypass aggressive CDN by requesting main.dart.js/sw.js with a query param and defaulting index.html to online first. This will not stop aggressive CDN caching of the index.html

#64968

* Add punctuation for unterminated sentences in doc comments

* Addressing review nit

The global packages path could cause tests to fail when it would be overriden to unexpected (in test setup) values. Remove most usage and make it a configuration on buildInfo, along with most other build information. Cleanup the asset builder to require the .packages path and the resident runners to no longer require it, since they already have the information in build_info.

It needs to stick around for the fuchsia deps we do not control.

Filled #60232 for remaining work.

Adds support for --bundle-sksl-path to windows, linux, macOS, and iOS.

Fixes #53115

update flutter_service_worker.js to NOTICES

Instead of targets/dart.dart -> targets/common.dart

Also combines experiments into extraGenSnapshot/ExtraFrontEndOptions. Allows providing --no-sound-null-safety to allow out of order migration and running.

Reland: #56167

This reverts commit f865ac7e.

* [flutter_tools] integration l10n tool

* add runtime skip to build system

* Update build_system.dart

* add links to issues, comments

* Update packages/flutter_tools/test/general.shard/build_system/build_system_test.dart
Co-authored-by: Shi-Hao Hong <shihaohong@google.com>

* Update packages/flutter_tools/lib/src/build_system/targets/localizations.dart
Co-authored-by: Shi-Hao Hong <shihaohong@google.com>

* Update localizations.dart

* switch to gen_l10n localizations

* fix tests
Co-authored-by: Shi-Hao Hong <shihaohong@google.com>

This reverts commit b8bd09db.

This reverts commit aed96199.

* [flutter_tools] supports tree-shake-icons for web builds

* Update compile.dart

* fix icon_tree_shaker