[MachineOutliner] Ensure AArch64 outliner doesn't mess with W30 or LR

Before, the outliner would mark all instructions that read from/modify LR as
illegal. This doesn't handle W30, which overlaps with LR. This shouldn't be
outlined.

This commit fixes that by making modifiesRegister() and readsRegister() look at
W30 + take in a TRI argument. This makes sure that modifiesRegister() and
readsRegister() won't outline either of W30 and LR.

https://reviews.llvm.org/D36435

llvm-svn: 310422