On 32-bit MIPS, 64-bit atomic ops are achieved through locks.
So allow the test to fail for atomic_intmax_t on 32-bit MIPS.
Change-Id: I78e7807e50f899a0fea0d5b388d9ebb53228aaa0
C11 defines the expected value to atomic_compare_exchange_* as being non-atomic
types. Using an atomic type is a syntax error in clang.
http://en.cppreference.com/w/c/atomic/atomic_compare_exchange
Change-Id: I74de1061fa1fc50d835451792d902000f368200e