Tweak a test so it's less flaky.
Add a WebDriverJs client to the SafariDriver's logging window so it's possible to use WebDriver from the devtools REPL on that page.  A WDJS client is still available to the extension's global page, but that page is only accessible from the extension builder (so it cannot be used once the extension has been packaged up for distribution).
Bump SafariDriver version and push a new prebuilt
Delete obsolete test.
Fix broken logging tests
Setup JS test targets for Safari
It should be possible to create a new session with WebDriverJs when running in a browser.

Fixes issue 5632.