[clang] [Driver][MachineOutliner] Support -moutline option for aarch64_be (PR #73223)

[Fangrui Song via cfe-commits]

================
@@ -2400,7 +2400,8 @@ void tools::addMachineOutlinerArgs(const Driver &D,
       // Otherwise, add the proper mllvm flags.
       if (!(Triple.isARM() || Triple.isThumb() ||
             Triple.getArch() == llvm::Triple::aarch64 ||
----------------
MaskRay wrote:

This can be simplified as `isAArch64()`

https://github.com/llvm/llvm-project/pull/73223