JBIDE-13004 Return back to WTP's original DirtyRegionProcessor clode after it is fixed in WTP 3.5

DirtyRegionProcesor WTP Class Copy is removed because upstream issues are fixed.

	modified:   common/plugins/org.jboss.tools.common.validation/src/org/jboss/tools/common/validation/java/JavaDirtyRegionProcessor.java
	deleted:    common/plugins/org.jboss.tools.common.validation/src/org/jboss/tools/common/validation/java/xpl/DirtyRegionProcessor.java
JBIDE-13246 added test case
small comments added. no jira