Add AArch64 support for restartable sequences
This covers adding AArch64 support to bring it into parity with x86 for restartable sequence ("rseq") handling which was added as part of #2350 (closed).
This covers adding AArch64 support to bring it into parity with x86 for restartable sequence ("rseq") handling which was added as part of #2350 (closed).