[heap] avoid limiting linear area for CompactionSpaces

There is no need to add speed-bumps for incremental marking purposes
for allocations from CompactionSpaces. This path was getting reached
for Parallel Scavenges.

Bug: 
Change-Id: I1f0f315549206bc86f8c48e202c29c18d212369b
Reviewed-on: https://chromium-review.googlesource.com/617920Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ali Ijaz Sheikh <ofrobots@google.com>
Cr-Commit-Position: refs/heads/master@{#47408}

src/heap/spaces.cc

@@ -2878,7 +2878,8 @@ HeapObject* FreeList::Allocate(size_t size_in_bytes) {
                               new_node->address() + size_in_bytes);
   } else if (bytes_left > kThreshold &&
              owner_->heap()->incremental_marking()->IsMarkingIncomplete() &&
-             FLAG_incremental_marking) {
+             FLAG_incremental_marking &&
+             !owner_->is_local()) {  // Not needed on CompactionSpaces.
     size_t linear_size = owner_->RoundSizeDownToObjectAlignment(kThreshold);
     // We don't want to give too large linear areas to the allocator while
     // incremental marking is going on, because we won't check again whether