Don't apply backoff time if the last compilation succeeded.

This change is supposed to be a no-op change, but it makes the logic
more straghtforward and therefore avoids potential pitfalls that can be
introduced by future changes.

Bug: 241512616
Change-Id: I4623b1f2cc1169d6405d850564d33a2f8c697524
Test: Presubmit
2 files changed