These changes were necessary to run with the new style of jsapi tests
introduced in https://github.com/WebAssembly/spec/pull/883.

Change-Id: I4629dd48d595ed97ed0607dec9e7d9808c706a7e
Reviewed-on: https://chromium-review.googlesource.com/c/1277724
Commit-Queue: Ben Smith <binji@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56745}