CRM_Core_BAO_SettingTest - Fix setting leakage which breaks CRM_Core_BAO_SettingTest

A previous commit fixed the leak out of CRM_Case_BAO_CaseTest, but there appears to be more.
This fix tries to be more aggressive about setting a general baseline.
CRM_Case_PseudoConstantTest - Fix

The old assertion was dependending on the previous test (e.g. the
list of case-types added/removed). By changing the base class
to CiviCaseTestCase, we get a more consistent (but different)
starting point.
Merge pull request #3980 from totten/4.5-component-tests

CRM_Core_BAO_SettingTest - Fix setting leakage which breaks CRM_Core_BAO_SettingTest