[AArch64] Implement extshx and extsbx.
[AArch64] Implement cntlzwx.
[AArch64] Implement negx.
[AArch64] Implement mcrf.
[AArch64] Implement mtsr and mfsr
[AArch64] Implement mtsprin and mfsprin
[AArch64] Implement mfmsr
[AArch64] Implement twi and tw.
Merge pull request #1130 from Sonicadvance1/AArch64-jit-extXx

[AArch64] Implement instructions.