[lldb] Fix cast-function-type-mismatch warning in Host.mm (NFC)

Fixes warning: cast from 'void (*)(xpc_object_t _Nonnull)' (aka 'void
(*)(NSObject<OS_xpc_object> * _Nonnull)') to 'xpc_finalizer_t' (aka
'void (*)(void * _Nullable)') converts to incompatible function type
[-Wcast-function-type-mismatch]

Author: JDevlieghere

lldb/source/Host/macosx/objcxx/Host.mm

@@ -891,6 +891,10 @@ static short GetPosixspawnFlags(const ProcessLaunchInfo &launch_info) {
   return flags;
 }
 
+static void finalize_xpc(void *xpc_object) {
+  xpc_release((xpc_object_t)xpc_object);
+}
+
 static Status LaunchProcessXPC(const char *exe_path,
                                ProcessLaunchInfo &launch_info,
                                lldb::pid_t &pid) {
@@ -956,7 +960,7 @@ static Status LaunchProcessXPC(const char *exe_path,
     }
   });
 
-  xpc_connection_set_finalizer_f(conn, xpc_finalizer_t(xpc_release));
+  xpc_connection_set_finalizer_f(conn, finalize_xpc);
   xpc_connection_resume(conn);
   xpc_object_t message = xpc_dictionary_create(nil, nil, 0);