js_ast: Avoid precedence issue with negative numbers as receivers at calls

tests/compiler/dart2js/js_constant_test.dart

Index: tests/compiler/dart2js/js_constant_test.dart
diff --git a/tests/compiler/dart2js/js_spec_optimization_test.dart b/tests/compiler/dart2js/js_constant_test.dart
similarity index 52%
copy from tests/compiler/dart2js/js_spec_optimization_test.dart
copy to tests/compiler/dart2js/js_constant_test.dart
index 3c03c09e299b70f0200740d27350348d77c4ee08..6165cfa8a59fb12073da751707b424ab533bff05 100644
--- a/tests/compiler/dart2js/js_spec_optimization_test.dart
+++ b/tests/compiler/dart2js/js_constant_test.dart
@@ -10,50 +10,9 @@ import 'compiler_helper.dart';
 const String TEST_1 = r"""
   import 'dart:_foreign_helper';
   main() {
-    // present: 'Moose'
-    JS('', 'Moose');
-
-    // absent: 'Phantom' - pure.
-    JS('returns: bool;effects:none;depends:none;throws:never', 'Phantom');
-
-    // present: 'Spider' - unused after constant folding 'is', but unpure.
-    print(JS('returns:bool;effects:none;depends:all', 'Spider') is bool);
-
-    // absent: 'Wasp' - unused after constant folding 'is', and unpure.
-    print(JS('returns:bool;effects:none;depends:all;throws:never', 'Wasp')
-          is bool);
-
-    JS('', 'Array');   // absent: "Array"
-  }
-""";
-
-const String TEST_2 = r"""
-  import 'dart:_foreign_helper';
-  main() {
-    var w1 = JS('returns:int;depends:none;effects:none;throws:never',
-        'foo(#)', 1);
-    var w2 = JS('returns:int;depends:none;effects:none;throws:never',
-        'foo(#)', 2);
-
-    print([w2, w1]);
-
-    // present: '[foo(2), foo(1)]' - since 'foo' is pure, we expect to generate
-    // code out-of-order.
-  }
-""";
-
-const String TEST_3 = r"""
-  import 'dart:_foreign_helper';
-  main() {
-    var s = JS('String|Null', '"Hello"');
-    var s1 = JS('returns:String;depends:none;effects:none;throws:null(1)',
-        '#.toLowerCase()', s);
-    var s2 = JS('returns:String;depends:none;effects:none;throws:null(1)',
-        '#.toUpperCase()', s);
-    print(s2);
-
-    // absent: 'toLowerCase' - removed since s.toUpperCase() generates the same
-    // noSuchMethod.
+    JS('', '#.toString()', -5);
+    // absent: "5.toString"
+    // present: "(-5).toString"
   }
 """;
 
@@ -89,7 +48,5 @@ main() {
 
   asyncTest(() => Future.wait([
     check(TEST_1),
-    check(TEST_2),
-    check(TEST_3),
   ]));
 }