Handle more unqualified SendSets

tests/compiler/dart2js/semantic_visitor_test_send_data.dart

 // Copyright (c) 2015, 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.
 
 part of dart2js.semantics_visitor_test;
 
 const Map<String, List<Test>> SEND_TESTS = const {
   'Parameters': const [
     // Parameters
     const Test('m(o) => o;',
@@ skipping 1513 matching lines @@
     // detect `dynamic` as a constant subexpression.
     const Test(
         '''
         m() { dynamic(null, 42); }
         ''',
         const Visit(VisitKind.VISIT_DYNAMIC_TYPE_LITERAL_INVOKE,
                     constant: 'Type',
                     arguments: '(null,42)')),
     const Test(
         '''
+        m() => dynamic = 42;
+        ''',
+        const Visit(VisitKind.VISIT_DYNAMIC_TYPE_LITERAL_SET,
+                    constant: 'dynamic',
+                    rhs: '42')),
+    const Test(
+        '''
         m() => dynamic += 42;
         ''',
         const Visit(VisitKind.VISIT_DYNAMIC_TYPE_LITERAL_COMPOUND,
-                    constant: 'Type',
+                    constant: 'dynamic',
                     operator: '+=',
                     rhs: '42')),
     const Test(
         '''
         m() => ++dynamic;
         ''',
         const Visit(VisitKind.VISIT_DYNAMIC_TYPE_LITERAL_PREFIX,
-                    constant: 'Type',
+                    constant: 'dynamic',
                     operator: '++')),
     const Test(
         '''
         m() => dynamic--;
         ''',
         const Visit(VisitKind.VISIT_DYNAMIC_TYPE_LITERAL_POSTFIX,
-                    constant: 'Type',
+                    constant: 'dynamic',
                     operator: '--')),
   ],
   'Assert': const [
     // Assert
     const Test(
         '''
         m() { assert(false); }
         ''',
         const Visit(VisitKind.VISIT_ASSERT, expression: 'false')),
     const Test(
@@ skipping 2246 matching lines @@
         '''
         m(a) => a ??= 42;
         ''',
         const Visit(
             VisitKind.VISIT_PARAMETER_COMPOUND,
             element: 'parameter(m#a)',
             operator: '??=',
             rhs: '42')),
   ],
 };