Closes https://github.com/flutter/flutter/issues/162041.
I also converted the `.sh` and `.bat` files (largely) to Dart, mostly
because I don't know enough Windows XP command prompt in order to make
the change safely. They should still run the same from the CI
bootstrapping, but most of the logic is now Dart code.
Will send a separate PR to update the `flutter/tests` PR template.
/cc @johnmccutchan @Piinks
This PR does two things. First, it reduces the verbosity in the customer_testing shard. We want to be less verbose because it's nigh on impossible to find anything when there's a failure in the verbose logs. Also, some additional comments are added to make following the breadcrumbs easier for the next person.
Second, it reverts a timeout that had been set to 90 minutes a while ago. It's no longer needed.
Fixes https://github.com/flutter/flutter/issues/120901.
* 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.
