dart2js cps: Introduce some built-in operators in type propagation.

pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.dart

Index: pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.dart
diff --git a/pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.dart b/pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.dart
index d7f4b4514a05fd36134f995bb45d96d04617f8b6..4b3ea71e949e4270440e9e250e38eca38e082630 100644
--- a/pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.dart
+++ b/pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.dart
@@ -324,8 +324,8 @@ class SExpressionStringifier extends Indentation implements Visitor<String> {
   }
 
   String visitTypeExpression(TypeExpression node) {
-    String args = node.arguments.map(access).join(', ');
-    return '(TypeExpression ${node.dartType.toString()} $args)';
+    String args = node.arguments.map(access).join(' ');
+    return '(TypeExpression ${node.dartType} ($args))';
   }
 
   String visitNonTailThrow(NonTailThrow node) {
@@ -335,8 +335,14 @@ class SExpressionStringifier extends Indentation implements Visitor<String> {
 
   String visitCreateInvocationMirror(CreateInvocationMirror node) {
     String selector = node.selector.name;
-    String args = node.arguments.map(access).join(', ');
-    return '(CreateInvocationMirror $selector $args)';
+    String args = node.arguments.map(access).join(' ');
+    return '(CreateInvocationMirror $selector ($args))';
+  }
+
+  String visitApplyBuiltinOperator(ApplyBuiltinOperator node) {
+    String operator = node.operator.toString();
+    String args = node.arguments.map(access).join(' ');
+    return '(ApplyBuiltinOperator $operator ($args))';
   }
 }