1deea714b3
Per feedback on D123086 after submit. Also added a test for vec_malloc et al attribute inference to show it's doing the right thing. The new tests exposed a defect, corrected by adding vec_free to the list of free functions in MemoryBuiltins.cpp, which had been overlooked all the way back in D94710, over a year ago. Differential Revision: https://reviews.llvm.org/D124859