Buggy edge case in get_user_capability_course

MDL-59897 broke an edge case that I just spotted while thinking about MDL-60043.

The broken case is this:

• Create a role R, with 'moodle/course:view' permission Not set at system level.
• Override the role in CourseCategory1 to Allow.
• Assign user role R in Course1 (which is inside that category).

get_user_capability_course('moodle/course:view', $userid) should return Course1, but does not.

I have a unit test to prove this.