dart2js CPS: simple inlining of static invocations.

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 71ff03dd8964bfa7642e793c62056935bab29f20..a04fb4eb5d170003055ba4d5d5961cfb0a0ed469 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
@@ -427,11 +427,11 @@ class ConstantStringifier extends ConstantValueVisitor<String, Null> {
   }
 
   String visitInterceptor(InterceptorConstantValue constant, _) {
-    return _failWith(constant);
+    return '(Interceptor "${constant.unparse()}")';
   }
 
   String visitSynthetic(SyntheticConstantValue constant, _) {
-    return _failWith(constant);
+    return '(Synthetic "${constant.unparse()}")';
   }
 
   String visitDeferred(DeferredConstantValue constant, _) {