Front-end infrastructure: Encapsulate semantic-level questions/actions about const/temp.

Much about const or temp is mechanical, about actual declaration,
while much is semantic, about something higher level.  This commit
checks every use everywhere, and for the high-level ones, substitutes
an encapsulated version instead.

glslang/Include/Types.h

@@ -411,6 +411,19 @@ public:
         clearLayout();
     }
 
+    // Drop just the storage qualification, which perhaps should 
+    // never be done, as it is fundamentally inconsistent, but need to
+    // explore what downstream consumers need.
+    // E.g., in a deference, it is an inconsistency between:
+    // A) partially dereferenced resource is still in the storage class it started in
+    // B) partially dereferenced resource is a new temporary object
+    // If A, then nothing should change, if B, then everything should change, but this is half way.
+    void makePartialTemporary()
+    {
+        storage      = EvqTemporary;
+        specConstant = false;
+    }
+
     TStorageQualifier   storage   : 6;
     TBuiltInVariable    builtIn   : 8;
     TPrecisionQualifier precision : 3;