Adding tests that would reliably reproduce shifted search.

This would guaranteed to repro b/118441555 before it was fixed.

The test doesn't use the most powerful feature of race condition
reproducer, which is enumerating all possible event sequences.

Instead, it uses explicit repro sequences, which makes the test much
faster.

Bug: 120628042
Test: The added test
Change-Id: I89a7a9964f160a8a20ba3d9dda2f248237713014
7 files changed