Tests: Exclude tests based on compilation flags, not API presence (3.x version)

Tests: Exclude tests based on compilation flags, not API presence (3.x version)

Introduces a new test API, `includesModule`. The method returns whether
a particular module like "ajax" or "deprecated" is included in the current
jQuery build; it handles the slim build as well. The util was created so that
we don't treat presence of particular APIs to decide whether to run a test as
then if we accidentally remove an API, the tests would still not fail.

Closes gh-5071
Fixes gh-5069
Ref gh-5046

(partially cherry picked from commit fae5fee8b435cc20352d28b0a384b9784b1ad9ed)