forgot to commit tests for GRAILS-3088

GRAILS-2741: Custom constraints provided by plugins are not available
when domain classes are initially processed (unless the plugin is loaded
before the domain class plugin), so the domain class constraints are
"refreshed" after all the plugins have loaded. The constraints of
embedded domain classes, though, weren't refreshed and so custom
constraints were not being triggered by the validation.

Now the DefaultGrailsDomainClass.refreshConstraints() method manually
refreshes the constraints of any component/embedded properties.

No need to maange metaClass manually in Groovy. Probably original code was transformed from Java to Groovy

added ability to changed type of

fix for GRAILS-3269 and GRAILS-3268

fix for GRAILS-3121