Fix build after CL collision

https://chromium-review.googlesource.com/c/v8/v8/+/1377455 and
https://chromium-review.googlesource.com/c/v8/v8/+/1363143 passed
the commit queue individually, but need a one-line adaptation in
order to work together.

TBR=jgruber@chromium.org

No-Tree-Checks: true
No-Try: true
Change-Id: Id04344f1440ffa797ca852aff63acbbcbe57065c
Reviewed-on: https://chromium-review.googlesource.com/c/1378690
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58257}

test/cctest/test-compiler.cc

@@ -916,7 +916,7 @@ static int AllocationSitesCount(Heap* heap) {
   int count = 0;
   for (Object* site = heap->allocation_sites_list();
        site->IsAllocationSite();) {
-    AllocationSite* cur = AllocationSite::cast(site);
+    AllocationSite cur = AllocationSite::cast(site);
     CHECK(cur->HasWeakNext());
     site = cur->weak_next();
     count++;