The official WPT runner supports a `<meta name=timeout content=long>`
tag to let tests opt-in to a longer timeout. Modify our harness to pass
that custom timeout to our runner, so that we don't incorrectly time
out if our default time is shorter than the requested one.
Previously, imported WPT tests didn't display any output if the
internals object was exposed. This change adds the condition that the
browser must also be running headlessly for test output to not be
displayed.
...when running in test mode. This cuts down on the time it takes to run
the imported WPT tests, and you can still get the full error by opening
tests in the browser.
And here's the wild part: instead of cloning WPT tests, import the
relevant WPT tests that this fixes into our own test suite.
This works by adding a small Ladybird-specific callback in
resources/testharnessreport.js (which is what that file is meant for!)
Note that these run as text tests, and so they must signal the runner
when they are done. Tests using the "usual" WPT harness should just
work, but tests that do something more freestyle will need manual
signaling if they are to be imported.
I've also increased the test timeout here from 30 to 60 seconds,
to accommodate the larger WPT-style tests.
