The reference implementation used in the tests does not fully match
the spec, so for the diverging cases we need to explicitly specify
the correct expectation.

Every single change in this patch has been verified against every
major JavaScript engine using eshost + jsvu. All implementations
match the spec (and the V8 implementation), with the following two
exceptions:

- One expectation was wrong because of a JavaScriptCore bug (that
  is, we inherited the incorrect expectation when importing the
  tests from WebKit). A comment was added for that one.
- This work resulted in the discovery of bugs in Moddable/XS:
  https://github.com/Moddable-OpenSource/moddable/issues/112

Change-Id: I05d91d7acc5c8765e941fcd68c1086c2694c710c
Reviewed-on: https://chromium-review.googlesource.com/c/1396081Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58546}