test: update http credentials tests

[dgozman]

We have tests that will never pass, currently marked as fail(true) - remove them.
Update all the rest to use non-deprecated {httpCredentials} option instead of setHTTPCredentials(), leaving just one to test the latter.

[aslushnikov]

• shall we still test these at least at some extend since we do ship them to users? The method might have shortcomings, but be should keep it tested as long as we ship it
• how come coverage test didn't fail miserably for this PR?!

[dgozman]

• shall we still test these at least at some extend since we do ship them to users? The method might have shortcomings, but be should keep it tested as long as we ship it

Yep, I left one test for this method.

• how come coverage test didn't fail miserably for this PR?!

Good point. Fixed, although our coverage always breaks. We need a better solution.

[aslushnikov]

Note: firefox linux coverage now fails