[heap] Limit number of compaction tasks

Use similar strategy to scavenger when calculating number of parallel
compaction tasks. Do not add task for each page but every fourth page.

Bug: chromium:1051883
Change-Id: Iaba3046de9c9a3ab63c0e7afcc6e4a9c398c5a10
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2054097Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66260}

src/heap/mark-compact.cc

@@ -387,8 +387,9 @@ int NumberOfAvailableCores() {
 
 int MarkCompactCollectorBase::NumberOfParallelCompactionTasks(int pages) {
   DCHECK_GT(pages, 0);
-  int tasks =
-      FLAG_parallel_compaction ? Min(NumberOfAvailableCores(), pages) : 1;
+  int tasks = FLAG_parallel_compaction ? Min(NumberOfAvailableCores(),
+                                             pages / (MB / Page::kPageSize) + 1)
+                                       : 1;
   if (!heap_->CanExpandOldGeneration(
           static_cast<size_t>(tasks * Page::kPageSize))) {
     // Optimize for memory usage near the heap limit.