[clang] [clang-tidy] Add performance-move-smart-pointer-contents check. (PR #66139)

[Congcong Cai via cfe-commits]

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+.. title:: clang-tidy - performance-move-smart-pointer-contents
+
+performance-move-smart-pointer-contents
+=======================================
+
+Given a smart pointer containing a movable type, such as a
+`std::unique_ptr<SomeProtocolBuffer>`, it's possible to move the contents of the
+pointer rather than the pointer itself (ie `std::move(*p)` rather than
+`*std::move(p)`). Doing so is a pessimization if the type cannot be efficiently
+moved, as the pointer will be quicker than a larger type.
+
----------------
HerrCai0907 wrote:

I think the performance issue will happened only when `SomeProtocolBuffer` is `is_trivially_move_constructible` and is a large type.
You will not get any benefit from 
```c++
  std::unique_ptr<int> p;
  int x = std::move(*p);
```
to
```c++
  std::unique_ptr<int> p;
  int x = *std::move(p);
```

https://github.com/llvm/llvm-project/pull/66139