Disable auto "debugger" call for tests

pkg/dev_compiler/test/browser/language_tests.js

Index: pkg/dev_compiler/test/browser/language_tests.js
diff --git a/pkg/dev_compiler/test/browser/language_tests.js b/pkg/dev_compiler/test/browser/language_tests.js
index 593b3a056eeb34a897a64976cf8b17e34ff8ecb3..4266b3c9bfd2fac226bbd7d03ef12642d163b167 100644
--- a/pkg/dev_compiler/test/browser/language_tests.js
+++ b/pkg/dev_compiler/test/browser/language_tests.js
@@ -9,6 +9,7 @@ define(['dart_sdk', 'async_helper', 'expect', 'unittest', 'is', 'require'],
   async_helper = async_helper.async_helper;
   let minitest = expect.minitest;
 
+  dart_sdk.dart.trapRuntimeErrors(false);
   dart_sdk._isolate_helper.startRootIsolate(function() {}, []);
   let html_config = unittest.html_config;
   // Test attributes are a list of strings, or a string for a single