test(effect): verify cleanupEffect clears multiple dependencies

[jh-leong]

Add a new test case to validate the cleanupEffect function when clearing multiple dependencies, extending test coverage beyond single dependencies.

Closes #5541.

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	86.5 kB	32.9 kB	29.7 kB
vue.global.prod.js	132 kB	49.6 kB	44.5 kB

Usages

Name	Size	Gzip	Brotli
createApp	48 kB	18.9 kB	17.2 kB
createSSRApp	51.2 kB	20.2 kB	18.4 kB
defineCustomElement	50.4 kB	19.7 kB	17.9 kB
overall	61.4 kB	23.7 kB	21.6 kB

[skirtles-code]

The test added here looks good to me.

This test was originally written to test this code:

core/packages/reactivity/src/effect.ts

Lines 142 to 150 in 46d3910

	function cleanupEffect(effect: ReactiveEffect) {
	const { deps } = effect
	if (deps.length) {
	for (let i = 0; i < deps.length; i++) {
	deps[i].delete(effect)
	}
	deps.length = 0
	}
	}

As explained in #5541, the existing tests all passed if the for loop was removed and replaced with code that just cleans up the first item in the array. In other words, nothing tests that the loop actually loops.

I've confirmed that this test does indeed fix the problem as originally described.

However...

Since this test was created, effect.ts has been rewritten. I'm not sure there's an equivalent loop in the new code. The closest I could find was this loop:

core/packages/reactivity/src/effect.ts

Lines 146 to 153 in 94b9b37

	function postCleanupEffect(effect: ReactiveEffect) {
	if (effect.deps.length > effect._depsLength) {
	for (let i = effect._depsLength; i < effect.deps.length; i++) {
	cleanupDepEffect(effect.deps[i], effect)
	}
	effect.deps.length = effect._depsLength
	}
	}

But if I make similar changes to that loop, so that it doesn't actually loop, this test doesn't catch that mistake. I haven't dug down in enough detail to figure out why.

That said, maybe that doesn't matter. The test itself makes sense and it does catch potential problems that the existing tests aren't testing.