GRAILS-5686 - Instead of nulling ConfigHolder.config after each test, restore it to what it was before the test.
GRAILS-5686 - Instead of nulling ConfigHolder.config after each test, restore it to what it was before the test.

erdi/grails-core,clockworkorange/grails-core,clockworkorange/grails-core,clockworkorange/grails-core,clockworkorange/grails-core,erdi/grails-core,clockworkorange/grails-core,erdi/grails-core