Remove dart2js unparse-tests for illegal syntax (+2 etc.).

tests/compiler/dart2js/unparser_test.dart

 // 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.
 
 import "package:expect/expect.dart";
 import 'parser_helper.dart';
 import 'mock_compiler.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/tree/tree.dart';
 
 testUnparse(String statement) {
@@ skipping 11 matching lines @@
   Expect.equals(code, unparse(node));
 }
 
 testUnparseTopLevelWithMetadata(String code) {
   testUnparseUnit(code);
   // TODO(ahe): Enable when supported.
   // testUnparseUnit('@foo $code');
 }
 
 testSignedConstants() {
-  testUnparse('var x=+42;');
-  testUnparse('var x=+.42;');
   testUnparse('var x=-42;');
   testUnparse('var x=-.42;');
-  testUnparse('var x=+0;');
-  testUnparse('var x=+0.0;');
-  testUnparse('var x=+.0;');
   testUnparse('var x=-0;');
   testUnparse('var x=-0.0;');
   testUnparse('var x=-.0;');
 }
 
 testGenericTypes() {
   testUnparse('var x=new List<List<int>>();');
   testUnparse('var x=new List<List<List<int>>>();');
   testUnparse('var x=new List<List<List<List<int>>>>();');
   testUnparse('var x=new List<List<List<List<List<int>>>>>();');
@@ skipping 286 matching lines @@
       ["foo()", "void bar()", "int baz(a)", "int boz(int a,int b)=null"]);
   testUnparseParameters(
       ["this.foo()",
        //"void this.bar()", // Commented out due to Issue 7852
        //"int this.baz(a)", // Commented out due to Issue 7852
        //"int this.boz(int a,int b)=null" // Commented out due to Issue 7852
        ]);
 }
 
 testSymbolLiterals() {
-  testUnparse("#+;");  
+  testUnparse("#+;");
   testUnparse("#-;");
   testUnparse("#*;");
   testUnparse("#/;");
   testUnparse("#~/;");
   testUnparse("#%;");
   testUnparse("#<;");
   testUnparse("#<=;");
   testUnparse("#>;");
   testUnparse("#>=;");
   testUnparse("#==;");
   testUnparse("#&;");
   testUnparse("#|;");
   testUnparse("#^;");
-  
+
   testUnparse("#a;");
   testUnparse("#a.b;");
   testUnparse("#a.b.c;");
   testUnparse("#aa.bb.cc.dd;");
 }
 
 main() {
   testSignedConstants();
   testGenericTypes();
   testForLoop();
   testEmptyList();
   testClosure();
   testIndexedOperatorDecl();
   testNativeMethods();
   testPrefixIncrements();
   testConstModifier();
   testSimpleObjectInstantiation();
   testLibraryName();
   testImport();
   testExport();
   testPart();
   testPartOf();
   testCombinators();
   testRedirectingFactoryConstructors();
   testClassDeclarations();
   testMixinApplications();
   testParameters();
   testSymbolLiterals();
 }