Fix clang 12 Wsuggest-override and Wsuggest-destructor-override


Change-Id: Ic44e24057b95bb014504f02a736fb4341afc8971
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/304856
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
diff --git a/tests/ArenaAllocTest.cpp b/tests/ArenaAllocTest.cpp
index 55c3c61..b186d59 100644
--- a/tests/ArenaAllocTest.cpp
+++ b/tests/ArenaAllocTest.cpp
@@ -55,7 +55,7 @@
     struct FooRefCnt : public SkRefCnt {
         FooRefCnt() : x(-2), y(-3.0f) { created++; }
         FooRefCnt(int X, float Y) : x(X), y(Y) { created++; }
-        ~FooRefCnt() { destroyed++; }
+        ~FooRefCnt() override { destroyed++; }
 
         int x;
         float y;