Increase ASYNCIFY_STACK_SIZE

[yar2001]

According to #112, I increase the ASYNCIFY_STACK_SIZE and add a test that will check if the option works

Based on my experiments, the relationship between ASYNCIFY_STACK_SIZE and max nesting levels is as follows:

ASYNCIFY_STACK_SIZE	Max Nesting Levels
4096 (default)	12
81920	297

But if not calling the asyncified function, the max nesting levels can reach up to around 962, maybe the ASYNCIFY_STACK_SIZE can continue to be increased?

---

I add a new commit that is using dynamic asyncify stack(emscripten-core/emscripten#9556) like this:

#ifdef QTS_ASYNCIFY
EM_JS(void, set_asyncify_stack_size, (size_t size), {
  Asyncify.StackSize = size || 81920;
});
#endif

/**
 * Set the stack size limit, in bytes. Set to 0 to disable.
 */
void QTS_RuntimeSetMaxStackSize(JSRuntime *rt, size_t stack_size) {
#ifdef QTS_ASYNCIFY
  set_asyncify_stack_size(stack_size);
#endif
  JS_SetMaxStackSize(rt, stack_size);
}

[justjake]

Looks great