fix(runtime-core): Error problem in custom instruction SSR environment

[Aaminly]

// runtime-core directives.ts withDirectives
if (dir && dir.deep) {
    traverse(value)
  }

// runtime-core directives.ts invokeDirectiveHook
let hook = binding && binding.dir && binding.dir[name] as DirectiveHook | DirectiveHook[] | undefined
if (__COMPAT__ && !hook) {
  hook = mapCompatDirectiveHook(name, binding.dir, instance)
}
if (hook) {

Both dir and binding may be undefined, resulting in a deep error

[edison1105]

I think if dir is undefined, it should jump out of the current loop.

[Aaminly]

Yes, we should really jump out of the loop. At present, such judgment and processing can also achieve the expected effect.

[Aaminly]

I don't have complete reading logic. Thank you for reminding me.

[posva]

Can you add a failing test case that would pass with this change?

[edison1105]

Suggested change

	if (!dir) continue;
	let [dir, value, arg, modifiers = EMPTY_OBJ] = directives[i]
	if (!dir) continue;

[Aaminly]

The main problem is that in the SSR environment, if an instruction is written on the label but not declared, an error will be reported, and the error information is not intuitive enough

[skirtles-code]

I believe this problem was fixed in #6671, so this PR can now be closed.