Review of diffs from lldb's internal debugserver and llvm.org main found
two orphaned changes that should be upstreamed.
First is in MachTask::ExceptionThread where we want to confirm that a
mach exception messages is from the correct process before we process
it.
Second is that we want to run the arm64 register context through
thread_convert_thread_state() after thread_get_state, and before
thread_set_state, to re-sign fp/sp/lr/pc appropriately for ptrauth
(arm64e) processes.
37cd595c1c