Remove appcache tests for fetch metadata.
We're generating these tests, but no browser supports the underlying
feature. Let's stop generating them.
Change-Id: I65092ac35c74227c4b24d95b4dc07beac5707628
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5490688
Commit-Queue: Mike West mkwst@chromium.org
Reviewed-by: Antonio Sartori antoniosartori@chromium.org
Cr-Commit-Position: refs/heads/main@{#1293613}