Provide isAnyClassReferenceType() on SILType.

Author: rjmccall

include/swift/SIL/SILType.h

@@ -290,6 +290,12 @@ class SILType {
   bool hasReferenceSemantics() const {
     return getSwiftRValueType().hasReferenceSemantics();
   }
+
+  /// Returns true if the referenced type is any sort of class-reference type,
+  /// meaning anything with reference semantics that is not a function type.
+  bool isAnyClassReferenceType() const {
+    return getSwiftRValueType().isAnyClassReferenceType();
+  }
 
   /// Returns true if the referenced type is guaranteed to have a
   /// single-retainable-pointer representation.