HLSL: Fix unary and binary operator type conversion issues

This fixes defects as follows:

1. handleLvalue could be called on a non-L-value, and it shouldn't be.

2. HLSL allows unary negation on non-bool values.  TUnaryOperator::promote
   can now promote other types (e.g, int, float) to bool for this op.

3. HLSL allows binary logical operations (&&, ||) on arbitrary types, similar
   (2).

4. HLSL allows mod operation on arbitrary types, which will be promoted.
   E.g, int % float -> float % float.

Test/hlsl.logical.binary.frag

@@ -0,0 +1,21 @@
+struct PS_OUTPUT
+{
+    float4 Color : SV_Target0;
+};
+
+uniform int    ival;
+uniform int4   ival4;
+uniform float  fval;
+uniform float4 fval4;
+
+PS_OUTPUT main()
+{
+    if (ival && fval);
+    if (ival || fval);
+
+    PS_OUTPUT psout;
+    psout.Color = 1.0;
+    return psout;
+}
+
+