qunit: Move modules exclusively for $wgEnableJavaScriptTest to test registry

These modules should only be loaded when $wgEnableJavaScriptTest
is true. Move these modules to the registry that is only activated
in that context and rename the modules to be namespaced under 'test.'
so that there is no mistake when referencing these that they are
not regularly available.

Change-Id: I21e69f50b006904b12fe9f79c196c903ebff4661
Merge "qunit: Move modules exclusively for $wgEnableJavaScriptTest to test registry"