[NewPM] Port for AArch64SLSHardening (#196378)
AArch64.h: Declared the AArch64SLSHardeningPass class.
AArch64PassRegistry.def: Registered the pass under the name
aarch64-sls-hardening.
AArch64SLSHardening.cpp: Implemented the run method to bridge the NewPM
with the existing pass logic, ensuring MachineModuleAnalysis is
correctly retrieved.
