qunit: Preserve context in QUnit module environment override

They were being called as properties of localEnv, which is a
shallow copy of the real one. When other callbacks add
properties to the object, they weren't visible in the local
"this" of the module teardown/setup.

Change-Id: I01e2031e1e2bfcedc7aa3480ce7d9915c8fff7f1
Merge "qunit: Preserve context in QUnit module environment override"