Fix infinite loop in GenerateIdentityHashCode

Root Cause:
  If no one changes the seed, it will become infinite loop due to below condition
    (expected_value & LockWord::kHashMask) == 0

Solution:
  Changes the seed before entering the next loop

Added test.

Bug: 19046417

Change-Id: I7d1c377dd1bda780681514b24d61ebc776bc80ab
3 files changed