Change coroutine testing for kotlinx.coroutines 1.9

See
https://github.com/Kotlin/kotlinx.coroutines/blob/master/kotlinx-coroutines-test/MIGRATION.md
for details.

Bug: 369137871
Flag: TEST_ONLY
Test: presubmits
Change-Id: I002033537eb0a5a591dd2b30546a0446c8b99225
Merged-In: I002033537eb0a5a591dd2b30546a0446c8b99225
(cherry picked from commit de414412)