At the moment we cancel all {AsyncCompileJobs} when a context of an
isolate gets disposed. However, there can be multiple contexts per
isolate, which meant that in some cases we canceled compilations even
though their context was still alive.

With this CL we only abort the compilations of the native context,
which is typically the context that is being disposed.

This is a small change that can be merged back. I plan to do a proper
change later which extends the V8 API so that the embedder provides
a handle to the context that is disposed.

R=clemensh@chromium.org

Bug: chromium:980876
Change-Id: I278bc30f084fe31fa409f1d4f913f1186b4809ec
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1692939
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62627}