Fixed crashes by adding missing call to EnsureSourcePositionsAvailable,
which requires clearing and restoring the pending exception.

> While most source positions were not collected even throwing exceptions,
> the top frame still was always collected as it was used to initialize
> the JSMessageObject. This skips even that frame, by storing the
> SharedFunctionInfo and bytecode offset in the JSMessageObject allowing
> it to lazily evaluate the actual source position.
>
> Also adds tests to test-api.cc that test each of the source position
> functions in isolation to ensure that they don't rely on previous
> invocations to call the source collection function.
>
> Since no source positions are now collected at the point when an
> exception is thrown, the mjsunit/stack-traces-overflow now passes again
> with the flag enabled. (cctest/test-cpu-profiler/Inlining2 is now the
> only failure).

Bug: v8:8510
Change-Id: Ifa5fe31d3db34a6c6d6a9cef3d646ad620dabd81
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1601270
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61372}