Mark Firefox/jsshell as failing on double_parse_test.

tests/corelib/corelib.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 == dart2dart]
 bool_from_environment2_test: Skip
 bool_from_environment_default_value_test: Skip
 bool_from_environment_test: Skip
 from_environment_const_type_test: Skip
 from_environment_const_type_undefined_test: Skip
@@ skipping 74 matching lines @@
 iterable_return_type_test/02: RuntimeError # Issue 13646
 
 [ $compiler == none && ($runtime == drt || $runtime == dartium || $runtime == ContentShellOnAndroid) ]
 main_test: Fail  # Dartium needs to check for both main() and main(args).
 
 [ $compiler == none && $runtime == ContentShellOnAndroid ]
 core_runtime_types_test: Pass, Fail # Issue 20525
 
 [ $runtime == ff || $runtime == jsshell ]
 unicode_test: Fail
+# Firefox takes advantage of the ECMAScript number parsing cop-out clause
+# (presumably added to allow Mozilla's existing behavior)
+# and only looks at the first 20 significant digits.
+# The Dart VM and the other ECMAScript implementations follow the correct
+# IEEE-754 rounding algorithm.
+double_parse_test: Fail, OK
 
 [ $runtime == ff || $runtime == jsshell || $runtime == safari || $runtime == safarimobilesim ]
 double_round3_test: Fail, OK # Runtime rounds 0.49999999999999994 to 1.
 double_round_to_double2_test: Fail, OK # Runtime rounds 0.49999999999999994 to 1.
 
 [ $runtime == opera ]
 core_runtime_types_test: Fail
 null_nosuchmethod_test: Fail # Issue: 7413
 unicode_test: Fail # Issue 14694
 
@@ skipping 113 matching lines @@
 num_parse_test: RuntimeError  # Issue 15316
 num_parse_test/01: RuntimeError  # Issue 15316
 
 [ $system == windows && $arch == x64 ]
 stopwatch_test: Skip  # Flaky test due to expected performance behaviour.
 
 [ $runtime != d8 ]
 # JSCRE does not pass all of the tests ported for irregexp.
 # Ignore all of the tests until irregexp is fully ported.
 regexp/*: Skip