ART: Continue adding override annotations

Use Clang-tidy's modernize-use-override to add more annotations. Ignore
inferred annotations on destructors.

Bug: 32619234
Test: mmma art
Change-Id: Ic432c928e398d44df9171e42db04ee19946e6887
diff --git a/runtime/gc/heap.cc b/runtime/gc/heap.cc
index e76d35d..b6610b7 100644
--- a/runtime/gc/heap.cc
+++ b/runtime/gc/heap.cc
@@ -2280,13 +2280,13 @@
     }
   }
 
-  virtual bool ShouldSweepSpace(space::ContinuousSpace* space ATTRIBUTE_UNUSED) const {
+  bool ShouldSweepSpace(space::ContinuousSpace* space ATTRIBUTE_UNUSED) const override {
     // Don't sweep any spaces since we probably blasted the internal accounting of the free list
     // allocator.
     return false;
   }
 
-  virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj)
+  mirror::Object* MarkNonForwardedObject(mirror::Object* obj) override
       REQUIRES(Locks::heap_bitmap_lock_, Locks::mutator_lock_) {
     size_t obj_size = obj->SizeOf<kDefaultVerifyFlags>();
     size_t alloc_size = RoundUp(obj_size, kObjectAlignment);