Cleanup the formatting of obj2yaml.cpp.

I couldn't touch this file and not clean it up some. These reformattings
brought to you by clang-format, with some minor adjustments by me. More
spring cleaning to follow here.
AArch64: remove barriers from AArch64 atomic operations.

I've managed to convince myself that AArch64's acquire/release
instructions are sufficient to guarantee C++11's required semantics,
even in the sequentially-consistent case.