* Fix AutofillCounterTest.TimeRanges deadlock with FlushForTesting
Brave's background services (AI Chat, etc.) trigger D-Bus operations
during browser initialization. The D-Bus thread runs in the thread pool
and posts replies back to the main thread via PostTaskAndReply. The
upstream test calls ThreadPoolInstance::FlushForTesting() which blocks
the main thread, preventing D-Bus reply callbacks from executing, causing
a deadlock.
Replace FlushForTesting() with content::RunAllTasksUntilIdle() which
uses FlushAsyncForTesting + RunLoop to pump the main thread message loop
while waiting for thread pool completion, avoiding the deadlock.
Resolves https://github.com/brave/brave-browser/issues/54038
* Address review: use filter file instead of #define DISABLED_
Use test/filters/browser_tests-linux.filter to disable the upstream
TimeRanges test (D-Bus deadlock is Linux-specific). Rename our fixed
test to TimeRanges_BraveFixFlush to avoid name collision.
* Address review: disable test on Linux via filter only
Remove the chromium_src test override and keep only the filter file
entry to disable AutofillCounterTest.TimeRanges on Linux.
Netzenbot
b602c4e091