[compiler-rt][hwasan] Decouple use of the TLS global for getting the shadow...

[compiler-rt][hwasan] Decouple use of the TLS global for getting the shadow base and using the frame record feature

This allows for using the frame record feature (which uses __hwasan_tls)
independently from however the user wants to access the shadow base, which
prior was only usable if shadow wasn't accessed through the TLS variable or ifuncs.

Frame recording can be explicitly set according to ShadowMapping::WithFrameRecord
in ShadowMapping::init. Currently, it is only enabled on Fuchsia and if TLS is
used, so this should mimic the old behavior.

Added an extra case to prologue.ll that covers this new case.

Differential Revision: https://reviews.llvm.org/D103841