* Flutter_tools for web platform: report error messages with stacks on toolExit

Print error messages and stacks in verbose mode before calling
`throwToolExit` on communication errors to chrome and dwds.

This will help us disagnose CI flakes:

Helps: https://github.com/flutter/flutter/issues/84012
Closes: https://github.com/flutter/flutter/issues/87149

* Added tests

* Extend timeout for testing failure to connect to chrome

* Update rest of chrome tests to await until matching is finished

Also, refactor internal code to do the same.

See https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#avoid-double-negatives-in-apis

[flutter_tools] Remove web specific vm_service handlers, move handler tests to single location (#80440)

[flutter_tools] separate concept of null safe language version from current language version (#79052)

* opt out the flutter tool

* oops EOF

* fix import

* Update tool_backend.dart

* Update daemon_client.dart

* fix more

* Add connectedVmServiceUri service extension and set from flutter_tools

Ensure attaching to an application with an existing DDS instance is not treated as a fatal error (#70847)

In principle this is backwards compatible; I just merged all the classes into one and deprecated everything that became redundant as a result.

This reverts commit 8749d955.

In principle this is backwards compatible; I just merged all the classes into one and deprecated everything that became redundant as a result.

[flutter_tools] use initially parsed package config for language version, sound mode determination (#70323)

Fixes #69416
Fixes #70121

Fixes #69348

If the web development server fails to bind, then retry up to 5 times. If a port was not provided, select a new free port each time.