[heap] Randomly abort evacuation while stress testing

Abort evacuation for ~10% of evacuation candidates during stress
testing. This should make aborting of evacuation more frequently and
uncover bugs sooner.

Bug: chromium:1359294, v8:12578
Change-Id: I2fb2124b10456ea71da12df71ef92cf2c3d89c03
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3878173
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83023}

src/heap/mark-compact.cc

@@ -4516,6 +4516,23 @@ void MarkCompactCollector::EvacuatePagesInParallel() {
     }
   }
 
+  if (v8_flags.stress_compaction || v8_flags.stress_compaction_random) {
+    // Stress aborting of evacuation by aborting ~10% of evacuation candidates
+    // when stress testing.
+    const double kFraction = 0.1;
+
+    for (Page* page : old_space_evacuation_pages_) {
+      if (page->IsFlagSet(Page::COMPACTION_WAS_ABORTED)) continue;
+
+      if (isolate()->fuzzer_rng()->NextDouble() < kFraction) {
+        ReportAbortedEvacuationCandidateDueToFlags(page->area_start(), page);
+        // Set this flag early on in this case to allow filtering such pages
+        // below.
+        page->SetFlag(Page::COMPACTION_WAS_ABORTED);
+      }
+    }
+  }
+
   for (Page* page : old_space_evacuation_pages_) {
     if (page->IsFlagSet(Page::COMPACTION_WAS_ABORTED)) continue;