MDL-43440 unit testing: Use cmid in unit tests when it should be used.

instance is has been used instead of cmid.  This works as all id's are 1
in most cases, but not always.

accesslib_clear_all_caches_for_unit_testing was updated to clear the
$USER->access cache which would fail test when the wrong user's data was used.

Conflicts from extra tests in master:
	blocks/comments/tests/events_test.php
	mod/assign/submission/comments/tests/events_test.php
	mod/data/tests/lib_test.php
	mod/glossary/tests/events_test.php

mod/data/tests/lib_test.php

@@ -104,4 +104,4 @@ class data_lib_testcase extends advanced_testcase {
         // Make sure the function returns true on a successful deletion.
         $this->assertTrue($result);
     }
-}
+}