[Triple] Use clang-format to normalize the formatting of the ARM target

[Triple] Use clang-format to normalize the formatting of the ARM target
parsing logic prior to making substantial changes to it.

This parsing logic is incredibly wasteful, so I'm planning to rewrite
it. Just unittesting the triple parsing logic spends well over 80% of
its time in the ARM parsing logic, and others have measured significant
time spent here in real production compiles.

Stay tuned...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246369 91177308-0d34-0410-b5e6-96231b3b80d8