build: fix build on msvc

See: https://github.com/nodejs/node-v8/issues/158#issuecomment-636909258
Change-Id: I50c732cd682cd4627a463822a4dfd1678dff266e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2226121Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68105}

src/heap/off-thread-heap.cc

@@ -19,6 +19,8 @@
 namespace v8 {
 namespace internal {
 
+OffThreadHeap::~OffThreadHeap() = default;
+
 OffThreadHeap::OffThreadHeap(Heap* heap)
     : space_(heap),
       lo_space_(heap),

src/heap/off-thread-heap.h

@@ -21,6 +21,7 @@ class OffThreadTransferHandleStorage;
 class V8_EXPORT_PRIVATE OffThreadHeap {
  public:
   explicit OffThreadHeap(Heap* heap);
+  ~OffThreadHeap();
 
   HeapObject AllocateRaw(int size, AllocationType allocation,
                          AllocationAlignment alignment = kWordAligned);