[turbofan] Remember source positions when creating graph from bytecode.

src/compiler/source-position.h

Index: src/compiler/source-position.h
diff --git a/src/compiler/source-position.h b/src/compiler/source-position.h
index d4df7835efc230a722dcab6e52dd8e109900ab0b..de60db17d40e9e4f07510df80b4200572935d321 100644
--- a/src/compiler/source-position.h
+++ b/src/compiler/source-position.h
@@ -72,6 +72,10 @@ class SourcePositionTable final : public ZoneObject {
   SourcePosition GetSourcePosition(Node* node) const;
   void SetSourcePosition(Node* node, SourcePosition position);
 
+  void set_current_position(int position) {
+    current_position_ = SourcePosition(position);
+  }
+
   void Print(std::ostream& os) const;
 
  private: