Aggressively apply the const lint.

* devicelab benchmarks run on Windows

* fix analyzer issue

* fix test

* fix pubspec

... and run some more tests on Windows.

* disables all `flutter test` and `flutter drive` tests on Windows as those two commands are not fully implemented on Windows yet
* fixes other failures on Windows

This reverts commit 8f273e49.

I ran the test 10 times on Linux and Mac and it succeeded
consistently. Let's reenable until there are new reports that it's
flaky.

Fixes #5901