Inject unique_ptr/shared_ptr into the test instead of using <memory>

[sbenza]

Summary

Inject unique_ptr/shared_ptr into the test instead of using <memory>
Libraries might not be present on tests.

[klimek]

lg

test/clang-tidy/redundant-smartptr-get-fix.cpp

 // RUN: $(dirname %s)/check_clang_tidy_fix.sh %s misc-redundant-smartptr-get %t
 
-#include <memory>
+namespace std {
+
+template <typename T>
+class unique_ptr {
+  T& operator*() const;
+  T* operator->() const;
+  T* get() const;
+};
+
+template <typename T>
+class shared_ptr {
+  T& operator*() const;
+  T* operator->() const;
+  T* get() const;
+};
+
+}  // namespace std
 
 struct Bar {
   void Do();
   void ConstDo() const;
 };
 struct BarPtr {
   Bar* operator->();
   Bar& operator*();

test/clang-tidy/redundant-smartptr-get.cpp

 // RUN: $(dirname %s)/check_clang_tidy_output.sh %s misc-redundant-smartptr-get
 
 // CHECK-NOT: warning
 
-#include <memory>
+namespace std {
+
+template <typename T>
+class unique_ptr {
+  T& operator*() const;
+  T* operator->() const;
+  T* get() const;
+};
+
+template <typename T>
+class shared_ptr {
+  T& operator*() const;
+  T* operator->() const;
+  T* get() const;
+};
+
+}  // namespace std
 
 struct int_ptr {
   int* get();
   int* operator->();
   int& operator*();
 };
 
 struct Bar {