Implement operator-is for interfaces' supertypes and String's supertypes. Also, improve stack trace…

dart/tests/language/language-leg.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.
 
 prefix language
 
 [ $component == leg && $checked ]
 *: Skip
 
 
@@ skipping 137 matching lines @@
 FactoryImplementationTest: Fail # Expect.equals(expected: <1>, actual: <0>) fails.
 GenericDeepTest: Fail # Expect.isTrue(false) fails.
 GenericInheritanceTest: Fail # Expect.isTrue(false) fails.
 GenericParameterizedExtendsTest: Fail # Expect.isTrue(false) fails.
 ImpliedInterfaceTest: Fail # Expect.equals(expected: <true>, actual: <false>) fails.
 InstFieldInitializerTest: Fail # Expect.equals(expected: <>, actual: <null>) fails.
 InstanceCompoundAssignmentOperatorTest: Fail # Expect.equals(expected: <4>, actual: <5>) fails.
 InstanceFieldInitializerTest: Fail # Expect.equals(expected: <1>, actual: <null>) fails.
 Instanceof2Test: Fail # Expect.equals(expected: <true>, actual: <false>) fails.
 IntrinsifiedMethodsTest: Fail # Expect.isTrue(false) fails.
-IsOperatorTest: Fail # Expect.equals(expected: <true>, actual: <false>) fails.
 LocalFunction3Test: Fail # Expect.equals(expected: <Closure>, actual: <Instance of 'Closure'>) fails.
 ListLiteral3Test: Fail # Expect.equals(expected: <true>, actual: <false>) fails.
 ListLiteral4Test: Fail # Expect.equals(expected: <110111>, actual: <null>) fails.
 PrivateMemberTest: Fail # uncaught exception in toString
 Private3Test: Fail # Expect.equals(expected: <-1>, actual: <The Ring>) fails.
 PrivateTest: Fail # Expect.equals(expected: <99>, actual: <499>) fails.
 PropertyFieldOverrideTest: Fail # Expect.equals(expected: <3>, actual: <null>) fails.
 ToStringAsFixedTest: Fail # Expect.equals(expected: <0.0000006>, actual: <0.0000010>) fails.
 TypedMessageTest: Fail # SyntaxError: Unexpected token this
 
 
 # Mapping of JS errors to Dart exceptions.
 Factory3Test: Fail # TypeError: Cannot call method 'prepend$1' of undefined
 MethodInvocationTest: Fail # TypeError: Cannot call method 'foo$0' of undefined
 NamedParametersPassingFalsyTest: Fail # TypeError: Object Instance of 'BoundClosure' has no method '$call$13'
 NullToStringTest: Fail # TypeError: Cannot call method 'get$toString' of undefined
 StackOverflowTest: Fail # RangeError: Maximum call stack size exceeded
 StackTraceTest: Fail # ReferenceError: stacktrace is not defined
 StringTest: Fail # TypeError: Object Hello has no method 'operator$indexSet$2'
 
 
-# Bad code.
-InstanceofTest: Fail # SyntaxError: Unexpected identifier
-
-
 #
 # The following tests are all semantic tests that we can rely on dartc
 # catching for now.
 #
 AbstractStaticNegativeTest: Fail, OK # Negative language test.
 AbstractSyntaxTest/01: Fail, OK # Negative language test.
 AbstractSyntaxTest/02: Fail, OK # Negative language test.
 AssignTopMethodNegativeTest: Fail, OK # Negative language test.
 BlackListedTest/01: Fail, OK # Negative language test.
 BlackListedTest/02: Fail, OK # Negative language test.
@@ skipping 131 matching lines @@
 # TODO(ahe): Categorize these failures.
 ClosureBreak1Test: Fail
 ClosureBreak2Test: Fail
 ClosureBreakTest: Fail
 ExecuteFinally3Test: Fail
 ExecuteFinally9Test: Fail
 
 
 [ $component == leg && $mode == release ]
 AssignTopMethodNegativeTest: Crash