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/libartbase/base/allocator.cc b/libartbase/base/allocator.cc
index 1bcfe87..6393672 100644
--- a/libartbase/base/allocator.cc
+++ b/libartbase/base/allocator.cc
@@ -30,11 +30,11 @@
   MallocAllocator() {}
   ~MallocAllocator() {}
 
-  void* Alloc(size_t size) {
+  void* Alloc(size_t size) override {
     return calloc(sizeof(uint8_t), size);
   }
 
-  void Free(void* p) {
+  void Free(void* p) override {
     free(p);
   }
 
@@ -49,12 +49,12 @@
   NoopAllocator() {}
   ~NoopAllocator() {}
 
-  void* Alloc(size_t size ATTRIBUTE_UNUSED) {
+  void* Alloc(size_t size ATTRIBUTE_UNUSED) override {
     LOG(FATAL) << "NoopAllocator::Alloc should not be called";
     UNREACHABLE();
   }
 
-  void Free(void* p ATTRIBUTE_UNUSED) {
+  void Free(void* p ATTRIBUTE_UNUSED) override {
     // Noop.
   }