Remove holders for runtime type information.

sdk/lib/_internal/compiler/implementation/ssa/builder.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/builder.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/builder.dart b/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
index cb9a7dd8c0f4b13e042f849f0047fb6b79765711..1f550ffdd18ab5ab85910987ed97f0ead808b969 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
@@ -2794,8 +2794,9 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
       HInstruction representations =
         buildTypeArgumentRepresentations(type);
       add(representations);
-      HInstruction isFieldName =
-          addConstantString(node, backend.namer.operatorIs(element));
+      String operator =
+          backend.namer.operatorIs(backend.getImplementationClass(element));
+      HInstruction isFieldName = addConstantString(node, operator);
       // TODO(karlklose): use [:null:] for [asField] if [element] does not
       // have a subclass.
       HInstruction asFieldName =