Fix type error in js_dart2js.dart caught by DDC.

pkg/dev_compiler/lib/js/common/dart_sdk.js

Index: pkg/dev_compiler/lib/js/common/dart_sdk.js
diff --git a/pkg/dev_compiler/lib/js/common/dart_sdk.js b/pkg/dev_compiler/lib/js/common/dart_sdk.js
index 7c7e31bca087e53c07ff6b2ace7ccab657e0a976..655e0e923a565ff550723dbd0734ec3d8a5cb91b 100644
--- a/pkg/dev_compiler/lib/js/common/dart_sdk.js
+++ b/pkg/dev_compiler/lib/js/common/dart_sdk.js
@@ -13514,7 +13514,31 @@
     if (privateSymbol != null) {
       return privateSymbol;
     }
-    return _js_mirrors.getName(symbol);
+    let name = _js_mirrors.getName(symbol);
+    switch (name) {
+      case '[]':
+      {
+        name = '_get';
+        break;
+      }
+      case '[]=':
+      {
+        name = '_set';
+        break;
+      }
+      case 'unary-':
+      {
+        name = '_negate';
+        break;
+      }
+      case 'constructor':
+      case 'prototype':
+      {
+        name = dart.str`_${name}`;
+        break;
+      }
+    }
+    return name;
   };
   dart.lazyFn(_js_mirrors._getMember, () => SymbolTodynamic());
   _js_mirrors._getNameForESSymbol = function(member) {