benchmarks/lockhammer/include/atomics.h

- mostly whitespace formatting
- prevent use of x86_64 assmebly when compiled with clang because there
  is some issue that needs to be debugged
- set cas64_acquire_release failure_memoryorder to __ATOMIC_RELAXED
  because it is not allowed to be __ATOMIC_ACQ_REL

Change-Id: I9ba370655fd49d0111b2587d6a158ec7c474c190

Author: jty2