Modified implementation of DataTypeManagerService due to interface update
Includes TestParser class
TEIID-2808: Small fixes to unit tests and accompanying classes

* TestParser
 * Removes extraneous code
 * Makes the test expected objects consistent with actual objects

* Block
 * Mistake in equals method checking exceptionGroup against itself rather
   than other.exceptionGroup

* ElementSymbol
 * Type of element symbol not being checked in equals method
Updates to conform with spi

* Removal of tests to test plugin
Response to moving Status enum in ValidatorFailure to api interface
Updates ExecutionAdminFactory with interface change
Satisfy change in interface for Teiid 8.7
Ensures classloader always present for UDFSource and SystemFunctionManager

* Since the loading of classes reflectively is so important for teiid
  functions, a classloader must be available to allow the plugin to find
  the necessary classes.
Merge branch 'teiid-client' into 8.4.x