Add missing dependency to emscripten_proxy_to_main_thread_js

Author: kleisauke

src/library_pthread.js

@@ -872,7 +872,7 @@ var LibraryPThread = {
 #endif
   },
 
-  emscripten_proxy_to_main_thread_js__deps: ['emscripten_run_in_main_runtime_thread_js'],
+  emscripten_proxy_to_main_thread_js__deps: ['$withStackSave', 'emscripten_run_in_main_runtime_thread_js'],
   emscripten_proxy_to_main_thread_js__docs: '/** @type{function(number, (number|boolean), ...(number|boolean))} */',
   emscripten_proxy_to_main_thread_js: function(index, sync) {
     // Additional arguments are passed after those two, which are the actual