[AArch64] Register passes so they can be run by llc

Initialize all AArch64-specific passes in the TargetMachine so they can be run
by llc. This can lead to conflicts in opt with some command line options that
share the same name as the pass, so I took this opportunity to do some cleanups:
* rename all relevant command line options from "aarch64-blah" to
  "aarch64-enable-blah" and update the tests accordingly
* run clang-format on their declarations
* move all these declarations to a common place (the TargetMachine) as opposed
  to having them scattered around (AArch64BranchRelaxation and
  AArch64AddressTypePromotion were the only offenders)

llvm-svn: 277322