Fixed --print-source crash.

BUG=v8:1866
TEST=d8 --print-source

Review URL: http://codereview.chromium.org/8969021

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10271 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/prettyprinter.cc

@@ -447,6 +447,7 @@ void PrettyPrinter::Print(const char* format, ...) {
 
 
 void PrettyPrinter::PrintStatements(ZoneList<Statement*>* statements) {
+  if (statements == NULL) return;
   for (int i = 0; i < statements->length(); i++) {
     if (i != 0) Print(" ");
     Visit(statements->at(i));