Clear caches between tests for ModuleStoreTestCase/SharedModuleStoreTestCase
Clear caches between tests for ModuleStoreTestCase/SharedModuleStoreTestCase

Cached values were leaking across tests, causing difficult to debug errors,
particularly when using Config Models. As part of this work, certain tests
that had query counts that relied on those values being cached needed to
be adjusted up.

bmedx/modulestore,bmedx/modulestore,bmedx/modulestore