[clang-tidy] Remove constructor with empty body

This constructor can be default, and since it isn't doing anything,
can be removed.

See
https://chromium.googlesource.com/chromium/src/+/HEAD/styleguide/c++/c++-dos-and-donts.md#prefer-to-use.

Bug: v8:10488
Change-Id: I5da7d78063c57d318f6cec578185bad6f83a1a3b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2233980
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68274}

src/heap/mark-compact.cc

@@ -2717,8 +2717,6 @@ static inline SlotCallbackResult UpdateStrongSlot(TSlot slot) {
 // It does not expect to encounter pointers to dead objects.
 class PointersUpdatingVisitor : public ObjectVisitor, public RootVisitor {
  public:
-  PointersUpdatingVisitor() {}
-
   void VisitPointer(HeapObject host, ObjectSlot p) override {
     UpdateStrongSlotInternal(p);
   }