Patch for awaitNanos() for coarse-grained clocks

If System.nanoTime() returns the same value twice in awaitNanos()
then (remaining == initialNanos) will be true but the code
will conclude that a (less likely) overflow occurred.

Bug: 24284239
(cherry-picked from commit 8fc2ac0f)
Change-Id: I3b9d573ea822e18f4c1849c8ab66071e66274a50