Lower map literals to constructor or function calls in builder

pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart

Index: pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart
diff --git a/pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart b/pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart
index 1c96301711577753d98346431fcc4e8fb7d3cc06..a972ecfb63be3bbf9da0511321693799e1a6dccf 100644
--- a/pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart
+++ b/pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart
@@ -737,15 +737,6 @@ class StatementRewriter extends Transformer implements Pass {
     return node;
   }
 
-  Expression visitLiteralMap(LiteralMap node) {
-    // Process arguments right-to-left, the opposite of evaluation order.
-    for (LiteralMapEntry entry in node.entries.reversed) {
-      entry.value = visitExpression(entry.value);
-      entry.key = visitExpression(entry.key);
-    }
-    return node;
-  }
-
   Expression visitTypeOperator(TypeOperator node) {
     _rewriteList(node.typeArguments);
     node.value = visitExpression(node.value);