ARM64: Fix for recording SP for handler.

ARM64: Fix for recording SP for handler.

Fixes https://github.com/dotnet/coreclr/issues/3701.

When GC occurs in a catch handler, we compare the current frame with the one
saved before the funclet was invoked.
The recorded SP address was wrong (offset by 16 byte), which caused FindParentStackFrameForStackWalk to null frame.
So, we ended up with assert on `ExceptionTracker::HasFrameBeenUnwoundByAnyActiveException(&m_crawl)`.
The issue was assembly helper, CallEHFunclet records FP instead of SP while SP is adjusted in prolog.