Fix runtimeType.toString for tear-offs.

pkg/compiler/lib/src/js_emitter/old_emitter/setup_program_builder.dart

Index: pkg/compiler/lib/src/js_emitter/old_emitter/setup_program_builder.dart
diff --git a/pkg/compiler/lib/src/js_emitter/old_emitter/setup_program_builder.dart b/pkg/compiler/lib/src/js_emitter/old_emitter/setup_program_builder.dart
index 58ad5bd8f634c6c66846aec8214d90cb4ade494b..87c7c0a3a91b4fdc66c4ed482fbfe9ab63616395 100644
--- a/pkg/compiler/lib/src/js_emitter/old_emitter/setup_program_builder.dart
+++ b/pkg/compiler/lib/src/js_emitter/old_emitter/setup_program_builder.dart
@@ -22,9 +22,6 @@ const RANGE3_ADJUST =
     - (FIRST_FIELD_CODE + RANGE1_SIZE + RANGE2_SIZE - RANGE3_FIRST);
 
 const String setupProgramName ='setupProgram';
-// TODO(floitsch): make sure this property can't clash with anything. It's
-//   unlikely since it lives on types, but still.
-const String typeNameProperty = r'builtin$cls';
 
 jsAst.Statement buildSetupProgram(Program program, Compiler compiler,
                                 JavaScriptBackend backend,
@@ -239,10 +236,10 @@ function $setupProgramName(programData, typesOffset) {
         body += "this." + #deferredActionString + "();";
       }
       str += ") {\\n" + body + "}\\n";
-      str += name + ".$typeNameProperty=\\"" + name + "\\";\\n";
       str += "\$desc=\$collectedClasses." + name + "[1];\\n";
       str += name + ".prototype = \$desc;\\n";
       if (typeof defineClass.name != "string") {
+        // IE does not store the name, but allows to modify the property.
         str += name + ".name=\\"" + name + "\\";\\n";
       }
       if (#hasIsolateSupport) {