[Java] Revert valueRef validation when presence is constant.

Author: mjpt777

sbe-tool/src/main/java/uk/co/real_logic/sbe/xml/Field.java

@@ -96,29 +96,6 @@ public void validate(final Node node)
 
         checkForValidName(node, name);
 
-        if (presence == Presence.CONSTANT && null != valueRef)
-        {
-            final String typeName = type == null ? null : type.name();
-
-            if (!(type instanceof EnumType))
-            {
-                handleError(node, "valueRef only valid for enum constants, type is " + typeName);
-            }
-
-            final int periodIndex = valueRef.indexOf('.');
-            if (periodIndex < 1 || periodIndex == (valueRef.length() - 1))
-            {
-                handleError(
-                    node, "valueRef format not valid for constant (enum-name.valid-value-name): " + valueRef);
-            }
-
-            final String valueRefType = valueRef.substring(0, periodIndex);
-            if (!valueRefType.equals(typeName))
-            {
-                handleError(node, "valueRef type " + valueRefType + " does not match " + typeName);
-            }
-        }
-
         if (type instanceof EnumType && presence == Presence.CONSTANT)
         {
             if (null == valueRef)