Fix new space allocation in parser which can be triggered on background compiler

runtime/vm/parser.h

Index: runtime/vm/parser.h
diff --git a/runtime/vm/parser.h b/runtime/vm/parser.h
index aac41b0af445965a5d02737e3d28d222e655bc84..c7f766efe829abc6ed46fa580f9fdca96c627e1c 100644
--- a/runtime/vm/parser.h
+++ b/runtime/vm/parser.h
@@ -949,6 +949,10 @@ class Parser : public ValueObject {
   Thread* thread_;    // Cached current thread.
   Isolate* isolate_;  // Cached current isolate.
 
+  // It is Heap::kNew for mutator thread and Heap::kOld for other threads (e.g.
+  // background compiler).
+  Heap::Space allocation_space_;
+
   Script& script_;
   TokenStream::Iterator tokens_iterator_;
   Token::Kind token_kind_;  // Cached token kind for current token.