This patch follows up on changes made by D99944 to test support for
unwinding stack when AArch64 pointer authentication feature is enabled.
We have already added logic to calculate code and data address masks which
will be utilized to mask off ignored bits from top of return address during the
stack trace calculation.
Default value of used address bits will be set to 52 which is maximum
possible AArch64 virtual address width. Addition logic has been added to
AArch64SVEReconfigure to detect pointer authentication feature for the
current process. If PAC is enabled, address bits in use are configured based on
PAC code/data mask.
This patch includes a test case to demonstrate successful back trace
calculation in presence of pointer authentication feature.