In order to keep track of where the return address is stored in each block, the
UnwindingInfoWriter needs to know if a block exits the current function.
However, we would only mark returns and tail-calls as exists, while we also have
kArchDebugAbort, kArchThrowTerminator and kArchDeoptimize. This would lead to
assertions when generating the snapshot in debug mode with
`v8_perf_prof_unwinding_info = true`.

Bug: v8:7660
Change-Id: Iee2ab222251f6922dd21442e12cbb6b56534bf54
Reviewed-on: https://chromium-review.googlesource.com/1019504Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#52906}