Fix audioflinger in integer sanitized builds.

Refactor threadLoop() to avoid unsigned integer overflows
which were causing errors on integer sanitized builds.

Also disable sanitization in fnv1a.

Bug: 30969751
Test: Compiles with and without integer sanitization.
Test: Device boots.
Change-Id: Ia8201e8a8f1d4df2b356ec81003fb07598db4546
Merged-In: Ia8201e8a8f1d4df2b356ec81003fb07598db4546
2 files changed