[gn] Enable stricter build flags

src/heap/heap-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_HEAP_INL_H_
 #define V8_HEAP_HEAP_INL_H_
 
 #include <cmath>
 
 #include "src/base/platform/platform.h"
@@ skipping 834 matching lines @@
   }
 }
 
 AlwaysAllocateScope::AlwaysAllocateScope(Isolate* isolate)
     : heap_(isolate->heap()) {
   heap_->always_allocate_scope_count_.Increment(1);
 }
 
 
 AlwaysAllocateScope::~AlwaysAllocateScope() {
-  heap_->always_allocate_scope_count_.Increment(-1);
+  heap_->always_allocate_scope_count_.Decrement(1);
 }
 
 
 void VerifyPointersVisitor::VisitPointers(Object** start, Object** end) {
   for (Object** current = start; current < end; current++) {
     if ((*current)->IsHeapObject()) {
       HeapObject* object = HeapObject::cast(*current);
       CHECK(object->GetIsolate()->heap()->Contains(object));
       CHECK(object->map()->IsMap());
     } else {
       CHECK((*current)->IsSmi());
     }
   }
 }
 
 
 void VerifySmisVisitor::VisitPointers(Object** start, Object** end) {
   for (Object** current = start; current < end; current++) {
     CHECK((*current)->IsSmi());
   }
 }
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_INL_H_