Merge pull request #35980 from ktoso/wip-locals-missing-flag

[Concurrency][Task Locals] Fix missing flag setting on next pointer

Author: ktoso

include/swift/ABI/Task.h

@@ -300,15 +300,15 @@ class AsyncTask : public HeapObject, public Job {
                 // therefore skip also skip pointing to that parent and point
                 // to whichever parent it was pointing to as well, it may be its
                 // immediate parent, or some super-parent.
-                item->next = reinterpret_cast<uintptr_t>(parentHead->getNext());
+                item->next = reinterpret_cast<uintptr_t>(parentHead->getNext()) |
                                   static_cast<uintptr_t>(NextLinkType::IsParent);
                 break;
               case NextLinkType::IsNext:
                 assert(false && "empty taskValue head in parent task, yet parent's 'head' is `IsNext`, "
                                 "this should not happen, as it implies the parent must have stored some value.");
                 break;
               case NextLinkType::IsTerminal:
-                item->next = reinterpret_cast<uintptr_t>(parentHead->getNext());
+                item->next = reinterpret_cast<uintptr_t>(parentHead->getNext()) | 
                                   static_cast<uintptr_t>(NextLinkType::IsTerminal);
                 break;
             }