[MachineOutliner][AArch64] WA for multiple stack fixup cases in MachineOutliner.

In cases where MachineOutliner candidates either are:

  * noreturn
  * have calls with no available LR or free regs
  * Don't use SP

we can end up hitting stack fixup code for the caller and the callee for
a FrameID of MachineOutlinerDefault. This triggers the assert:

  `assert(OF.FrameConstructionID != MachineOutlinerDefault &&
          "Can only fix up stack references once");`

in AArch64InstrInfo.cpp. This assert exists for now because a lot of the
fixup code is not tested to handle fixing up more than once and needs
some better checks and enhancements to avoid potentially generating
illegal code.

I've filed a Bugzilla report to track this until these cases are handled
by the AArch64 MachineOutliner: https://bugs.llvm.org/show_bug.cgi?id=46767

This diff detects cases that will cause these multiple stack fixups and
prune the Candidates from `RepeatedSequenceLocs`.

    Differential Revision: https://reviews.llvm.org/D83923

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