Bump the version; we're promoting 1.2-beta3 to 1.2-rc1
Set __attribute__ ((noinline)) on our getPC function.

This prevents clang from inlining PC fetching from the link register.
Enable the LR test for ARM64.
Expand the valid address range for armv7 devices with optimization enabled.

This works for now, but the test should be instrumented to eliminate the fragility
of PC checking.
Ensure that UNWIND_COMPACT and UNWIND_DWARF are enabled for release builds on all architectures other than arm32.

Related to PLCR-504.
Bump RC version to 1.2-rc2