Assign yield ids in ast-numbering rather than in bytecode-generator.

src/ast/prettyprinter.cc

Index: src/ast/prettyprinter.cc
diff --git a/src/ast/prettyprinter.cc b/src/ast/prettyprinter.cc
index 4f95d914d0a7649083f4c17bb5d29184a658f2b2..efd2d4c697a27c617d71f20536b742bf645506b1 100644
--- a/src/ast/prettyprinter.cc
+++ b/src/ast/prettyprinter.cc
@@ -1609,7 +1609,9 @@ void AstPrinter::VisitAssignment(Assignment* node) {
 
 
 void AstPrinter::VisitYield(Yield* node) {
-  IndentedScope indent(this, "YIELD", node->position());
+  EmbeddedVector<char, 128> buf;
+  SNPrintF(buf, "YIELD id %d", node->yield_id());
+  IndentedScope indent(this, buf.start(), node->position());
   Visit(node->expression());
 }