Add names for mach-o permissions bits and use the symbol names in place of magic numbers

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190013 91177308-0d34-0410-b5e6-96231b3b80d8
mi-sched: Force bottom up scheduling for generic targets.

Fast register pressure tracking currently only takes effect during
bottom up scheduling. Forcing this is a bit faster and simpler for
targets that don't have many scheduling constraints and don't need
top-down scheduling.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190014 91177308-0d34-0410-b5e6-96231b3b80d8