There is a fallback in Module->getConfig() to the global services
container. This is not meant to be used in practice, but there were
two places where this was missing: WebInstallerOutput, and various
PHPUnit tests.
* Add missing setConfig() to WebInstallerOutput.
* Add missing setConfig() to various tests. Most tests were already
doing this correctly and using the standard mock from
ResourceLoaderTestCase. Upon switching the last few tests as well,
I uncovered various errors due to the mock missing some settings
that the tested code uses, so these have been added now to
ResourceLoaderTestCase.
Bug: T277728
Change-Id: I44f16ec4e00423fb6f641e58fffc1d40e4571f01
b7c70526a9