fix make_exception_ptr_with violation of warning class-memaccess under gcc-12

Summary:
Fix this build failure:
```
folly/lang/Exception.cpp: In instantiation of ‘std::__exception_ptr::exception_ptr folly::detail::make_exception_ptr_from_rep_(Value) [with Value = void*]’:
folly/lang/Exception.cpp:724:40:   required from here
folly/lang/Exception.cpp:707:14: warning: ‘void* memcpy(void*, const void*, size_t)’ writing to an object of type ‘class std::__exception_ptr::exception_ptr’ with no trivial copy-assignment; use copy-assignment or copy-initialization instead [-Wclass-memaccess]
  707 |   std::memcpy(&ptr, &value, sizeof(value));
      |   ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /opt/rh/gcc-toolset-12/root/usr/include/c++/12/exception:168,
                 from folly/lang/Exception.h:20,
                 from folly/lang/Exception.cpp:17:
/opt/rh/gcc-toolset-12/root/usr/include/c++/12/bits/exception_ptr.h:90:11: note: ‘class std::__exception_ptr::exception_ptr’ declared here
   90 |     class exception_ptr
      |           ^~~~~~~~~~~~~
```

Reviewed By: dmm-fb

Differential Revision: D76616506

fbshipit-source-id: 45bf3a716303e0efb6c22ee0f840c3b4ee5983d9

Author: yfeldblum

third-party/folly/src/folly/lang/Exception.cpp

@@ -704,7 +704,7 @@ static std::exception_ptr make_exception_ptr_from_rep_(Value value) noexcept {
   static_assert(sizeof(std::exception_ptr) == sizeof(Value));
   static_assert(alignof(std::exception_ptr) == alignof(Value));
   std::exception_ptr ptr;
-  std::memcpy(&ptr, &value, sizeof(value));
+  std::memcpy(static_cast<void*>(&ptr), &value, sizeof(value));
   return ptr;
 }