Fix -Wnon-virtual-dtor by making the ctor protected

GitOrigin-RevId: f8af06d60d9c5bcf6104bf6540350fb0fb1d7ac5
diff --git a/include/llvm/ProfileData/SampleProfileLoaderBaseImpl.h b/include/llvm/ProfileData/SampleProfileLoaderBaseImpl.h
index 0345496..60f117c 100644
--- a/include/llvm/ProfileData/SampleProfileLoaderBaseImpl.h
+++ b/include/llvm/ProfileData/SampleProfileLoaderBaseImpl.h
@@ -73,6 +73,7 @@
   void dump() { Reader->dump(); }
 
 protected:
+  ~SampleProfileLoaderBaseImpl() = default;
   friend class SampleCoverageTracker;
 
   unsigned getFunctionLoc(Function &F);