Reland "[heap] minor cleanup in allocation observer code"

This is a reland of 86da38fd
Original change's description:
> [heap] minor cleanup in allocation observer code
> 
> Change-Id: If0bec38d41a415e9fbfff57ac891de0461bac13b
> Reviewed-on: https://chromium-review.googlesource.com/668836
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Ali Ijaz Sheikh <ofrobots@google.com>
> Cr-Commit-Position: refs/heads/master@{#48046}

Change-Id: If5fd9f7d123a62672d5a4450ddeac5a6e29158b8
Reviewed-on: https://chromium-review.googlesource.com/675423
Commit-Queue: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-by: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49786}

src/heap/spaces.cc

@@ -1653,7 +1653,7 @@ Address PagedSpace::ComputeLimit(Address start, Address end,
     // Keep the linear allocation area to fit exactly the requested size.
     return start + size_in_bytes;
   } else if (!allocation_observers_paused_ && !allocation_observers_.empty() &&
-             identity() == OLD_SPACE && !is_local()) {
+             SupportsInlineAllocation()) {
     // Generated code may allocate inline from the linear allocation area for
     // Old Space. To make sure we can observe these allocations, we use a lower
     // limit.

src/heap/spaces.h

@@ -2232,7 +2232,9 @@ class V8_EXPORT_PRIVATE PagedSpace : NON_EXPORTED_BASE(public Space) {
   }
   void DecreaseLimit(Address new_limit);
   void StartNextInlineAllocationStep() override;
-  bool SupportsInlineAllocation() { return identity() == OLD_SPACE; }
+  bool SupportsInlineAllocation() {
+    return identity() == OLD_SPACE && !is_local();
+  }
 
  protected:
   // PagedSpaces that should be included in snapshots have different, i.e.,