double_to_string_as_fixed now works on Firefox.

tests/language/language_dart2js.status

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 [ $compiler == dart2js || $compiler == dart2dart ]
 class_literal_test/01: Fail # Class literals are expression now; delete this test.
 class_literal_test/02: Fail # Class literals are expression now; delete this test.
 class_literal_test/05: Fail # Class literals are expression now; delete this test.
 class_literal_test/06: Fail # Class literals are expression now; delete this test.
 class_literal_test/07: Fail # Class literals are expression now; delete this test.
@@ skipping 323 matching lines @@
 [ $compiler == dart2js && $mode == release ]
 assign_top_method_test: Fail
 
 
 [ $compiler == dart2js && $runtime == none ]
 *: Fail, Pass # TODO(ahe): Triage these tests.
 
 
 [ $compiler == dart2js && ($runtime == ff || $runtime == jsshell)]
 call_through_null_getter_test: Fail # Expected: ObjectNotClosureException got: Instance of 'TypeError'
-double_to_string_as_fixed_test: Fail
 
 [ $compiler == dart2js && $runtime == ie9 ]
 div_by_zero_test: Fail
 double_to_string_as_fixed_test: Fail
 expect_test: Fail
 factory3_test: Fail
 stack_overflow_test: Fail
 type_checks_in_factory_method_test: Fail
 
 
@@ skipping 17 matching lines @@
 method_invocation_test: Fail
 null_pointer_exception_test: Fail
 stack_overflow_test: Fail
 string_interpolate_npe_test: Fail
 closure_call_wrong_argument_count_negative_test: Skip
 label_test: Skip
 
 [ $runtime == d8 ]
 # Timer interface not supported.
 typed_message_test: Fail