[X86] When using "and $0" and "orl $-1" to store 0 and -1 for minsize, make...

[X86] When using "and $0" and "orl $-1" to store 0 and -1 for minsize, make sure the store isn't volatile

If the store is volatile this might be a memory mapped IO access. In that case we shouldn't generate a load that didn't exist in the source

Differential Revision: https://reviews.llvm.org/D50270

llvm-svn: 339041