[heap] SimulateFullSpace needs to run in safepoint

Run SimulateFullSpace in safepoint. Needed for FreeLinearAllocationArea
which would race with concurrent allocation.

Bug: v8:10315
Change-Id: If0c3c4e20edea1b05cc1a3e1a3e37fc29254a196
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2354812Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69395}

test/cctest/heap/heap-utils.cc

@@ -187,6 +187,7 @@ void SimulateIncrementalMarking(i::Heap* heap, bool force_completion) {
 }
 
 void SimulateFullSpace(v8::internal::PagedSpace* space) {
+  SafepointScope scope(space->heap());
   CodeSpaceMemoryModificationScope modification_scope(space->heap());
   i::MarkCompactCollector* collector = space->heap()->mark_compact_collector();
   if (collector->sweeping_in_progress()) {