[gn] Enable stricter build flags

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index c61dfd54d495136549e2bc734ca743795144538e..7a9af9939f2d8c2a562b235262943e7d5b1fb959 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -1646,15 +1646,15 @@ class Heap {
   }
 
   inline bool ShouldReduceMemory() const {
-    return current_gc_flags_ & kReduceMemoryFootprintMask;
+    return (current_gc_flags_ & kReduceMemoryFootprintMask) != 0;
   }
 
   inline bool ShouldAbortIncrementalMarking() const {
-    return current_gc_flags_ & kAbortIncrementalMarkingMask;
+    return (current_gc_flags_ & kAbortIncrementalMarkingMask) != 0;
   }
 
   inline bool ShouldFinalizeIncrementalMarking() const {
-    return current_gc_flags_ & kFinalizeIncrementalMarkingMask;
+    return (current_gc_flags_ & kFinalizeIncrementalMarkingMask) != 0;
   }
 
   void PreprocessStackTraces();