[runtime] Drop FIRST/LAST_NONCALLABLE_SPEC_OBJECT instance type range.

src/full-codegen/arm64/full-codegen-arm64.cc

Index: src/full-codegen/arm64/full-codegen-arm64.cc
diff --git a/src/full-codegen/arm64/full-codegen-arm64.cc b/src/full-codegen/arm64/full-codegen-arm64.cc
index fe7ad4bb580c178b82a9581862cb81d5f7d31af3..1ac0596001c802b0e82e7f2abacde1a912de886d 100644
--- a/src/full-codegen/arm64/full-codegen-arm64.cc
+++ b/src/full-codegen/arm64/full-codegen-arm64.cc
@@ -3034,25 +3034,17 @@ void FullCodeGenerator::EmitClassOf(CallRuntime* expr) {
 
   VisitForAccumulatorValue(args->at(0));
 
-  // If the object is a smi, we return null.
+  // If the object is not a JSReceiver, we return null.
   __ JumpIfSmi(x0, &null);
-
-  // Check that the object is a JS object but take special care of JS
-  // functions to make sure they have 'Function' as their class.
-  // Assume that there are only two callable types, and one of them is at
-  // either end of the type range for JS object types. Saves extra comparisons.
-  STATIC_ASSERT(NUM_OF_CALLABLE_SPEC_OBJECT_TYPES == 2);
+  STATIC_ASSERT(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
   __ CompareObjectType(x0, x10, x11, FIRST_JS_RECEIVER_TYPE);
   // x10: object's map.
   // x11: object's type.
   __ B(lt, &null);
 
-  __ Cmp(x11, LAST_JS_RECEIVER_TYPE);
-  STATIC_ASSERT(LAST_NONCALLABLE_SPEC_OBJECT_TYPE ==
-                LAST_JS_RECEIVER_TYPE - 1);
+  // Return 'Function' for JSFunction objects.
+  __ Cmp(x11, JS_FUNCTION_TYPE);
   __ B(eq, &function);
-  // Assume that there is no larger type.
-  STATIC_ASSERT(LAST_NONCALLABLE_SPEC_OBJECT_TYPE == LAST_TYPE - 1);
 
   // Check if the constructor in the map is a JS function.
   Register instance_type = x14;