Second try at fixing frog. Tests failed only in checked mode.

tests/language/language.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.
 
 # This directory contains tests that are intended to show the
 # current state of the language.
 
 # In order to maintain maximum test coverage for all builds,
 # please use the following procedure to mark a test
 # failed on architectures other than the one you are working on.
@@ skipping 164 matching lines @@
 [ $compiler == frog && $unchecked ]
 BoolTest: Fail # Issue 2092
 CompileTimeConstantCTest/01: Fail # integers as keys in literal maps.
 Operator4Test: Fail
 
 [ $compiler == frog ]
 StaticInitializerTypeErrorTest: Fail # Checked mode not implemented.
 ExceptionTest: Fail # Issue 1785
 Factory3Test: Fail # Issue 417
 Factory2NegativeTest: Fail
-FBoundedQuantificationTest/01: Fail # Issue 439
-FBoundedQuantificationTest/02: Fail # Issue 439
 CallThroughNullGetterTest: Fail # Throw ObjectNotClosure instead of NullPointerException.
 CompileTimeConstantCTest/02: Fail # string-concatenated (+) keys in literal maps.
 CompileTimeConstantDTest: Fail # doesn't recognize 400 + z (with z parameter of constructor) as compile-time constant.
 CompileTimeConstantETest: Fail
 CompileTimeConstantGTest: Fail # compile time constants with super calls to optional arguments.
 CompileTimeConstantKTest: Fail # Constant maps are not canonicalized correctly if the same key appears multiple times.
 CompileTimeConstantLTest: Fail # final instance fields with default values are not initialized correctly.
 CompileTimeConstantOTest: Fail # String constants with string-interpolation.
 CompileTimeConstantPTest/01: Fail # Implicit super calls that don't match are not caught in compile-time constants.
 DisablePrivacyTest: Skip  # Issue 1882: Needs --disable_privacy support.
@@ skipping 203 matching lines @@
 [ $runtime == safari && ($system == linux || $system == windows) ]
 *: Skip
 
 [ $compiler == frog && $unchecked ]
 PrivateMemberTest/01: Fail # test seems bad - see issue #353
 PrivateMemberTest/02: Fail # test seems bad - see issue #353
 PrivateMemberTest/03: Fail # test seems bad - see issue #353
 PrivateMemberTest/04: Fail # test seems bad - see issue #353
 
 [ $compiler == frog && $checked ]
+FBoundedQuantificationTest/01: Fail # Issue 439
+FBoundedQuantificationTest/02: Fail # Issue 439
 PrivateMemberTest/none: Fail # test seems bad - see issue #353
 AssignStaticTypeTest/01: Fail # Unrecognized option: --no-enable-type-checks.
 AssignStaticTypeTest/02: Fail # Unrecognized option: --no-enable-type-checks.
 AssignStaticTypeTest/03: Fail # Unrecognized option: --no-enable-type-checks.
 AssignStaticTypeTest/04: Fail # Unrecognized option: --no-enable-type-checks.
 TypeVariableBoundsTest/01: Fail # Issue 2135
 TypeVariableBoundsTest/02: Fail # Issue 2135
 TypeVariableBoundsTest/05: Fail # Issue 2135
 TypeVariableBounds2Test/00: Fail # Issue 2135
 TypeVariableBounds2Test/03: Fail # Issue 2135
@@ skipping 24 matching lines @@
 
 [ $compiler == frog && $runtime == none ]
 *: Skip
 
 [ $arch == simarm ]
 *: Skip
 
 [ $arch == arm ]
 *: Skip