[destructuring] Implement parameter pattern matching.

src/prettyprinter.cc

Index: src/prettyprinter.cc
diff --git a/src/prettyprinter.cc b/src/prettyprinter.cc
index 284beadfeedb5a7dc64472a6372a4091e6a42eff..8685781445a36c83d8fc6bd2c478ea72db24346e 100644
--- a/src/prettyprinter.cc
+++ b/src/prettyprinter.cc
@@ -993,7 +993,7 @@ void PrettyPrinter::PrintParameters(Scope* scope) {
   Print("(");
   for (int i = 0; i < scope->num_parameters(); i++) {
     if (i  > 0) Print(", ");
-    PrintLiteral(scope->parameter(i)->name(), false);
+    PrintLiteral(scope->parameter_var(i)->name(), false);
   }
   Print(")");
 }
@@ -1124,8 +1124,8 @@ void AstPrinter::PrintParameters(Scope* scope) {
   if (scope->num_parameters() > 0) {
     IndentedScope indent(this, "PARAMS");
     for (int i = 0; i < scope->num_parameters(); i++) {
-      PrintLiteralWithModeIndented("VAR", scope->parameter(i),
-                                   scope->parameter(i)->name());
+      PrintLiteralWithModeIndented("VAR", scope->parameter_var(i),
+                                   scope->parameter_var(i)->name());
     }
   }
 }