PR sanitizer/80953
	Merge from LLVM revision 355965
	* sanitizer_common/sanitizer_linux.cc (GetWriteFlag): Implement for
	SPARC/Linux.
	(GetPcSpBp): Likewise.
	* sanitizer_common/sanitizer_stacktrace.cc (GetNextInstructionPc):
	Adjust for SPARC.
	* sanitizer_common/sanitizer_stacktrace.h (SANITIZER_CAN_FAST_UNWIND):
	Define to 1 for SPARC.
	* sanitizer_common/sanitizer_stacktrace_sparc.cc: Rewrite.
	* sanitizer_common/sanitizer_unwind_linux_libcdep.cc (SlowUnwindStack):
	Adjust the PC address for SPARC with GCC.

From-SVN: r269638