Refactor test runner to use static list of resource paths

Previously everything lived in an inner class method of
SettingsRobolectricTestRunner. That method has now been turned into
a static method so that it can be called by other runners.

Bug: 62460102
Test: robotests
Change-Id: I6612b1f26404587301c534c8ba60e39d59d6c840
406 files changed