Among other stuff, this allows to use predefined .option.machine_version_major
/minor/stepping symbols in the directive.
Relevant test expanded at once (also file renamed for clarity).
Differential Revision: https://reviews.llvm.org/D28140
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290710 91177308-0d34-0410-b5e6-96231b3b80d8
