* opt out the flutter tool

* oops EOF

* fix import

* Update tool_backend.dart

* Update daemon_client.dart

* fix more

* Reland: Handle more cases where the tool receives RPCError 112

* Add null-aware access

This reverts commit c87f15fe.

Rolls in several fixes to web tooling, including better handling of absolute file imports. Updates to latest vm service to unblock null safety mode query
Co-authored-by: Gary Roumanis <grouma@google.com>
Co-authored-by: Anna Gringauze <annagrin@google.com>

This would help us investigate issues like
https://github.com/flutter/flutter/issues/64781

Removes global variables and adds unit tests that can be copied for #65118