HLSL: Move frexp() to a separate test file.

Test/hlsl.intrinsic.frexp.vert

@@ -0,0 +1,28 @@
+float VertexShaderFunctionS(float inF0, float inF1)
+{
+    frexp(inF0, inF1);
+    return 0.0;
+}
+
+float2 VertexShaderFunction2(float2 inF0, float2 inF1)
+{
+    frexp(inF0, inF1);
+    return float2(1,2);
+}
+
+float3 VertexShaderFunction3(float3 inF0, float3 inF1)
+{
+    frexp(inF0, inF1);
+    return float3(1,2,3);
+}
+
+float4 VertexShaderFunction4(float4 inF0, float4 inF1)
+{
+    frexp(inF0, inF1);
+    return float4(1,2,3,4);
+}
+
+// TODO: FXC doesn't accept this with (), but glslang doesn't accept it without.
+#define MATFNS() \
+    frexp(inF0, inF1);
+