[heap] Remove Capacity DCHECK in Expand.

This DCHECK does not hold for compaction spaces that may go over the limit
with large semi-spaces and small old generation size maxima.

Bug: chromium:855960
Change-Id: I39eea4c974b94c170e7314471fb1c50f9a1a2b45
Reviewed-on: https://chromium-review.googlesource.com/1126392Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54226}

src/heap/spaces.cc

@@ -1675,7 +1675,6 @@ bool PagedSpace::Expand() {
   AddPage(page);
   Free(page->area_start(), page->area_size(),
        SpaceAccountingMode::kSpaceAccounted);
-  DCHECK(Capacity() <= heap()->MaxOldGenerationSize());
   return true;
 }