COEP: test that <meta http-equiv> is not supported

[zcorpan]

No description provided.

[foolip]

Test looks good, and https://wpt.fyi/results/html/cross-origin-embedder-policy/meta-http-equiv.https.html?sha=f174353edd&label=pr_head shows all browser passing, which makes sense for a negative test.

[zcorpan]

Thanks, @foolip.

I also verified that the test does what I expect by adding a .headers file that sets the COEP header and running with wpt serve in Chrome Canary with "Cross Origin Isolation" pref enabled, which failed the test. (I believe it's not possible to set arbitrary prefs for wpt run, so I was lucky that COEP didn't require a secure context to do its thing!)

[zcorpan]

Actually, @jugglinmike pointed out that --binary-arg is a thing: https://web-platform-tests.org/running-tests/command-line-arguments.html?highlight=binary-arg#Configuration