[heap] Bound number of tasks by embedder limit instead of artificially capping

src/heap/mark-compact.h

Index: src/heap/mark-compact.h
diff --git a/src/heap/mark-compact.h b/src/heap/mark-compact.h
index 7303f071881abc3d36a1f75abfe677862c22fd6d..ab75dbfeda1fe5c342e504b9709dd2b75edc49b2 100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -327,6 +327,9 @@ class MarkCompactCollectorBase {
   // Returns whether this page should be moved according to heuristics.
   bool ShouldMovePage(Page* p, intptr_t live_bytes);
 
+  int NumberOfParallelCompactionTasks(int pages);
+  int NumberOfPointerUpdateTasks(int pages);
+
   Heap* heap_;
 };