fix make_exception_ptr_with build under wasm after D74343701

Summary: {D74343701} attempted to fix the exception destructor function-pointer type but was incomplete.

Reviewed By: Millsky

Differential Revision: D74480608

fbshipit-source-id: 2028c99b43e8f0d1e5ff84233faf8e6ea98e5b79

Author: yfeldblum

folly/lang/Exception.cpp

@@ -170,11 +170,13 @@ namespace __cxxabiv1 {
 
 //  the definition until llvm v10.0.0-rc2
 struct __folly_cxa_exception_sans_reserve {
+  using dtor_ret_t = std::conditional_t<folly::kIsArchWasm, void*, void>;
+
 #if defined(__LP64__) || defined(_WIN64) || defined(_LIBCXXABI_ARM_EHABI)
   size_t referenceCount;
 #endif
   std::type_info* exceptionType;
-  void (*exceptionDestructor)(void*);
+  dtor_ret_t (*exceptionDestructor)(void*);
   void (*unexpectedHandler)();
   std::terminate_handler terminateHandler;
   __folly_cxa_exception_sans_reserve* nextException;
@@ -197,12 +199,14 @@ struct __folly_cxa_exception_sans_reserve {
 
 //  the definition since llvm v10.0.0-rc2
 struct __folly_cxa_exception_with_reserve {
+  using dtor_ret_t = std::conditional_t<folly::kIsArchWasm, void*, void>;
+
 #if defined(__LP64__) || defined(_WIN64) || defined(_LIBCXXABI_ARM_EHABI)
   void* reserve;
   size_t referenceCount;
 #endif
   std::type_info* exceptionType;
-  void (*exceptionDestructor)(void*);
+  dtor_ret_t (*exceptionDestructor)(void*);
   void (*unexpectedHandler)();
   std::terminate_handler terminateHandler;
   __folly_cxa_exception_with_reserve* nextException;

folly/lang/Exception.h

@@ -746,7 +746,7 @@ struct make_exception_ptr_with_arg_ {
       : size{sizeof(E)},
         type{FOLLY_TYPE_INFO_OF(E)},
         ctor{make<F, E>},
-        dtor{kIsArchWasm ? dtor_<E> : thunk::dtor<E>} {}
+        dtor{dtor_<E>} {}
 };
 
 std::exception_ptr make_exception_ptr_with_(