This reverts commit 5fd259be.

* Use `dart __deprecated_pub` instead of `pub` to invoke pub from tools

The top level `pub` commmand has been deprecated and will print
a message. It is however implemented via the __deprecated_pub command
that prints no message.

This reverts commit 7c24ff2c.

Top level `pub` is being deprecated.

* Randomize tests, exclude tests that fail with randomization.

* Disable some more tool tests

Disable the automatic "pub get" if the project is using a third-party tool for linking dependencies. (#86177)

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

This reverts commit 8b6baae4.

Our current top crasher is an unclear error when ProcessManager fails to resolve an executable path. To fix this, we'd like to being adjusting the process resolution logic and adding more instrumentation to track failures. In order to begin the process, the ProcessManager has been folded back into the flutter tool

* opt out the flutter tool

* oops EOF

* fix import

* Update tool_backend.dart

* Update daemon_client.dart

* fix more

Disabled caching of pub invocations on flutter drive.

This reverts commit ff953e4f.

Fixes #69416
Fixes #70121

Necessary to work around #70013 (this looks like it will be fixed, but should protect us in the future)

Restores some notion of skipping pub, with differences from the prior implementation:

Off by default, and only used by the flutter command automatic pub get
A single check parameter. Uses the framework version cached per-project instead of a timestamp of the tool, to avoid cases where downloading a prebuilt framework would cause this check to no longer work.