[MPS][BE] Add virtual destructor (pytorch#141476)

As classes with virtual methods must have virtual destructors
Pull Request resolved: pytorch#141476
Approved by: https://github.com/cyyever, https://github.com/Skylion007
ghstack dependencies: pytorch#141474, pytorch#141475

Author: malfet

aten/src/ATen/native/mps/MetalShaderLibrary.h

@@ -18,6 +18,7 @@ class MetalShaderLibrary {
         nparams(nparams_),
         compile_options(compile_options_) {}
   MetalShaderLibrary(const MetalShaderLibrary&) = delete;
+  virtual ~MetalShaderLibrary() = default;
   inline id<MTLComputePipelineState> getPipelineStateForFunc(
       const std::string& fname) {
     return getLibraryPipelineState(getLibrary(), fname).first;