This stores a type alias in the global class list, so we can get
to the declarable and figure out namespace / file.

R=szuend@chromium.org

Bug: v8:7793
Change-Id: I2164b77e559d28fa18da12192a34e0a7264b858e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1613989
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61566}