As the comment indicates, this fixes a DCHECK failure, although I don’t
quite understand why it is happening in the first place.

Termination exceptions are similar to uncaught exceptions in that they
should clear the async id stack, because no ongoing async callbacks
will be brought to completion when execution terminates.

Previously, there was a check that made sure that that happened when
the termination occurred during the callback itself, but no such check
was in place for the case that the termination occurred during
microtasks started by them. This commit adds such a check, both for
microtasks and the `nextTick` queue. The latter addition doesn’t fix
a crash, but still makes sense conceptually.

The condition here is also flipped from applying only on Worker threads
to also applying on the main thread, and setting the `failed_` flag
rather than reading it. The former makes sense because the public C++
`Stop(env)` API can have the same effect as worker thread termination,
but on the main thread rather than a Worker thread.

Add regression tests for the case in which an async_hook is enabled
inside a Worker thread and `process.exit()` is called during the
async part of an async function.

This commit includes multiple tests that seem like they should all
crash in a similar way, but interestingly don’t. In particular, it’s
surprising that the presence of a statement after `process.exit()`
in a function has an effect on the kind of crash that’s being
exhibited (V8 DCHECK vs. assertion in our own code) and the
circumstances under which it crashes (e.g. the -1 and -2 tests
can be “fixed” by reverting 13c5a16, although they
should have the same behavior as the -3 and -4 tests).

…raction

Co-authored-by: Colin Ihrig <cjihrig@gmail.com>