Currently, when loading a module, if the module is found in the cache, it's
immediately returned. However, that can result in a timing issue where the
module is cached, but not evaluated, and doesn't have an associated promise.
This commit tries to ensure a module is always evaluated and that the cache
entry has a module promise.
This might fix an crash handler issue. I couldn't reproduce the issue though.
I believe it requires specific timing which is hard to reproduce in a test.
1d03b688d9