[JSTesting] Fix static html tests

[JSTesting] Fix static html tests
* r107919 merge broke it as it removed all the inline mw.config calls, and the tearDown is resetting them to the initial values. That works fine on a MediaWiki page but on the static page are now no variables at all. Copying a basic sample to it. This should've been in the static test suite all along actually.
* Calculating wgScriptPath based on location.pathname instead of location.href, exclude wgServer
* Follows-up r107919