Full stack: distinguish between a scalar and a vector of size 1.

There have been GLSL extensions considering this, and HLSL does it.
This is a fully backward compatible change that allows this distinction.

hlsl/hlslGrammar.cpp

@@ -219,8 +219,12 @@ bool HlslGrammar::acceptType(TType& type)
         new(&type) TType(EbtInt);
         break;
     case EHTokFloat:
+        new(&type) TType(EbtFloat);
+        break;
+
     case EHTokFloat1:
         new(&type) TType(EbtFloat);
+        type.makeVector();
         break;
 
     case EHTokFloat2: