LibWeb: Updates to increase test runnability of WPT

[ADKaster]

• Stub out WebDriver deserialize as a proxy capability AO
• Unblock port 9000
• Implement document.elementsFromPoint (not to be confused with elementFromPoint)

Brings the WPT infrastructure/ directory to the following (with SSL cert checking disabled)

Ran 148 tests finished in 617.0 seconds.
  • 37 ran as expected. 0 tests skipped.
  • 39 tests had errors unexpectedly
  • 21 tests failed unexpectedly
  • 26 tests timed out unexpectedly
  • 32 tests had unexpected subtest results

On master it's not actually possible to run all these tests b/c of the proxy capability issue.

Before the elementsFromPoint commit, the results are like so:

Ran 148 tests finished in 732.1 seconds.
  • 36 ran as expected. 0 tests skipped.
  • 43 tests had errors unexpectedly
  • 21 tests failed unexpectedly
  • 29 tests timed out unexpectedly
  • 25 tests had unexpected subtest results