Support isampler throughout the compiler.

TRAC #23359
Signed-off-by: Jamie Madill
Signed-off-by: Shannon Woods
Author: Nicolas Capens
diff --git a/src/compiler/Intermediate.cpp b/src/compiler/Intermediate.cpp
index e016af2..7042657 100644
--- a/src/compiler/Intermediate.cpp
+++ b/src/compiler/Intermediate.cpp
@@ -432,12 +432,10 @@
     //
     // Does the base type allow operation?
     //
-    switch (node->getBasicType()) {
-        case EbtVoid:
-        case EbtSampler2D:
-        case EbtSamplerCube:
-            return 0;
-        default: break;
+    if (node->getBasicType() == EbtVoid ||
+        IsSampler(node->getBasicType()))
+    {
+        return 0;
     }
 
     //