Revert all the changes to equals operator. Causing buildbot trouble.

tests/co19/co19-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.
 
 [ $compiler == dart2js && $system == macos && $runtime == d8 ]
 LibTest/core/Math/acos_A01_t01: Fail, OK
 LibTest/core/Math/asin_A01_t01: Fail, OK
 LibTest/core/Math/atan_A01_t01: Fail, OK
 
 [ $compiler == dart2js && $system == windows && $runtime == d8 ]
@@ skipping 329 matching lines @@
 
 [ $compiler == dart2js && $runtime == d8 ]
 Language/11_Statements/09_Try_A05_t03: Fail # Expect.isTrue(false) fails.
 Language/11_Statements/09_Try_A02_t02: Fail, OK # Expects to catch null if throwing null. We now throw NullPointerException which isn't caught.
 Language/11_Statements/14_Throw_A03_t02: Fail # Expect.isTrue(false) fails.
 Language/11_Statements/14_Throw_A03_t03: Fail # Expect.isTrue(false) fails.
 Language/13_Types/4_Interface_Types_A12_t12: Fail # Expect.isFalse(true) fails.
 Language/13_Types/4_Interface_Types_A12_t16: Fail # Expect.isFalse(true) fails.
 LibTest/core/Date/Date.fromString_A03_t01: Fail # Issue co19 - 121
 LibTest/core/Expect/throws_A02_t01: Fail # reason (sdsds sd dsf) not mentioned in ExpectException message (Expect.isTrue(false) fails.)
-LibTest/core/Expect/equals_A01_t03: Fail # not following the spec and expects the user-defined equality operator
-                                         # to be called when comparing for equality with null.
-LibTest/core/Expect/notEquals_A01_t03: Fail # not following the spec and expects the user-defined equality operator
-                                            # to be called when comparing for equality with null.
 LibTest/core/Math/parseDouble_A02_t01: Fail # Expect.fail('BadNumberFormatException is expected')
 LibTest/core/Queue/iterator_A01_t01: Fail # Expect.isFalse(true) fails.
 LibTest/core/RegExp/Pattern_semantics/firstMatch_CharacterEscape_A06_t02: Fail # IllegalJSRegExpException: '\c(' 'SyntaxError: Invalid regular expression: /\c(/: Unterminated group'
 LibTest/core/RegExp/Pattern_semantics/firstMatch_DecimalEscape_A01_t02: Fail # Expect.fail('Some exception expected')
 LibTest/core/RegExp/Pattern_semantics/firstMatch_NonEmptyClassRanges_A01_t05: Fail # Expect.fail('Some exception expected')
 LibTest/core/RegExp/Pattern_semantics/firstMatch_NonEmptyClassRanges_A01_t06: Fail # Expect.fail('Some exception expected')
 
 Language/10_Expressions/06_Lists_A07_t02: Fail # generic type information is lost during canonicalization.
 Language/10_Expressions/07_Maps_A06_t02: Fail # generic type information is lost during canonicalization.
 Language/10_Expressions/13_Function_Invocation/4_Function_Expression_Invocation_A05_t01: Fail # TypeError: Object #<Closure> has no method 'call'
@@ skipping 333 matching lines @@
 Language/12_Libraries_and_Scripts/2_Imports_A07_t01: Fail, OK # @compile-error
 Language/12_Libraries_and_Scripts/2_Imports_A07_t02: Fail, OK # @compile-error
 Language/12_Libraries_and_Scripts/2_Imports_A08_t02: Fail, OK # @compile-error
 Language/12_Libraries_and_Scripts/3_Includes_A01_t01: Fail, OK # @compile-error
 Language/12_Libraries_and_Scripts/3_Includes_A03_t03: Fail, OK # @compile-error
 Language/13_Types/3_Type_Declarations/1_Typedef_A07_t02: Fail, OK # @compile-error
 Language/13_Types/3_Type_Declarations/1_Typedef_A07_t03: Fail, OK # @compile-error
 Language/13_Types/7_Type_Void_A01_t02: Fail, OK # @compile-error
 Language/14_Reference/1_Lexical_Rules/1_Reserved_Words_A30_t04: Fail, OK # @compile-error
 Language/14_Reference/1_Lexical_Rules_A02_t06: Fail, OK # @compile-error