The inspector fuzzer is terminating the isolate after two seconds. At
this point, we can be in pretty much any state, and any further JS
execution would fail.
This CL fixes an issue where we got the termination signal when creating
a context for a regexp (while installing extensions).
There might be more places that need fixing, but with this CL the linked
issue does not reproduce locally any more, so it's a step forward.

R=szuend@chromium.org, bmeurer@chromium.org

Bug: chromium:1166549
Change-Id: I33b48205b71877aca6cfe5267f353fa899bfa05c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2636153Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72156}