[vm, gc] Fix untracked pointer in DeoptContext.

Bug: https://github.com/dart-lang/sdk/issues/35547
Change-Id: I610b2ad863c973fe2c46787c07e4be39aea8eb89
Reviewed-on: https://dart-review.googlesource.com/c/88288
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
diff --git a/runtime/vm/deopt_instructions.cc b/runtime/vm/deopt_instructions.cc
index 7015a75..0f499e1 100644
--- a/runtime/vm/deopt_instructions.cc
+++ b/runtime/vm/deopt_instructions.cc
@@ -184,6 +184,7 @@
 }
 
 void DeoptContext::VisitObjectPointers(ObjectPointerVisitor* visitor) {
+  visitor->VisitPointer(reinterpret_cast<RawObject**>(&code_));
   visitor->VisitPointer(reinterpret_cast<RawObject**>(&object_pool_));
   visitor->VisitPointer(reinterpret_cast<RawObject**>(&deopt_info_));