OGM-274 Fix BuiltinTypeTest#testStringMappedTypeSerialisation(

https://hibernate.onjira.com/browse/OGM-274

removed from the testStringMappedTypeSerialisation() method of BuiltInTypeTest class  the 2 lines:
 
assertEquals( "Entity user id incorrect", entity.get( "userId" ), userId );
assertEquals( "Entity stock count incorrect", entity.get( "stockCount" ), stockCount );

where a String (actual value) is compared with a Long and an Integer (expected value)