Fix line number table generation for multiline strings with interpolation.

runtime/vm/object.h

Index: runtime/vm/object.h
diff --git a/runtime/vm/object.h b/runtime/vm/object.h
index 2c302960bbf2948c949f955b03dc5dbf46e1d4c8..78120298251c26f5eb1d7aa6af955b554d98e2be 100644
--- a/runtime/vm/object.h
+++ b/runtime/vm/object.h
@@ -2398,6 +2398,7 @@ class Script : public Object {
   bool HasSource() const;
   RawString* Source() const;
   RawString* GenerateSource() const;  // Generates source code from Tokenstream.
+  RawGrowableObjectArray* GenerateLineNumberArray() const;
   RawScript::Kind kind() const {
     return static_cast<RawScript::Kind>(raw_ptr()->kind_);
   }