Add a shrinking reduction for dead continuation parameters.

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 58af3e84b0b5f04119cb3ea11e9cef7e24ca5357..a23b683ab93de15589b97b4b087af1c92ed3b04d 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
@@ -158,11 +158,10 @@ class SExpressionStringifier extends Visitor<String> with Indentation {
   }
 
   String visitInvokeContinuation(InvokeContinuation node) {
-    String cont = access(node.continuation);
+    String name = access(node.continuation);
+    if (node.isRecursive) name = 'rec $name';
     String args = node.arguments.map(access).join(' ');
-    String op =
-        node.isRecursive ? 'InvokeContinuation*' : 'InvokeContinuation';
-    return '$indentation($op $cont ($args))';
+    return '$indentation($InvokeContinuation $name ($args))';
   }
 
   String visitBranch(Branch node) {