Add testdriver support for WebDriver BiDi

[sadym-chromium]

Implement RFC 185: Add WebDriver BiDi support to testdriver.js. Based on https://github.com/web-platform-tests/wpt/pull/44649.

Addition to the RFC:

• Decline and fail test on user prompt in test window.

Open question:

• How to handle infrastructure/webdriver/bidi tests?

Blocked by:

• http://crrev.com/c/5568670 till Tue, Jun 11, 2024, when it reaches stable. Tracking.

[mathiasbynens]

This is now ready for reviews. @foolip @jgraham @gsnedders any thoughts?

[Ms2ger]

I understood that @jgraham wanted to take another look at this

[foolip]

@sadym-chromium did you see this error in infastructure/ tests?

Unexpected Results
------------------
/infrastructure/expected-fail/user-prompt.html?type=confirm
  UNEXPECTED-OK /infrastructure/expected-fail/user-prompt.html?type=confirm
ERROR BiDi event processing failed: unexpected alert open (500): unexpected alert open: {Alert text : this user prompt should be dismissed}
  (Session info: chrome=128.0.6583.0)

[sadym-chromium]

@sadym-chromium did you see this error in infastructure/ tests?

Unexpected Results
------------------
/infrastructure/expected-fail/user-prompt.html?type=confirm
  UNEXPECTED-OK /infrastructure/expected-fail/user-prompt.html?type=confirm
ERROR BiDi event processing failed: unexpected alert open (500): unexpected alert open: {Alert text : this user prompt should be dismissed}
  (Session info: chrome=128.0.6583.0)

this is related to https://crbug.com/42323841, WIP on chrtomedriver side.