[ARM] Generate ABI_optimization_goals build attribute, as described in the ARM ARM.

Summary: This reverts r254234, and adds a simple fix for the annoying case of use-after-free.

Reviewers: rengolin

Subscribers: aemerson, llvm-commits, rengolin

Differential Revision: http://reviews.llvm.org/D15236

llvm-svn: 254912