test: fix flaky should reload test fail

[sapphi-red]

Description

close #485

Additional context

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the PR Title Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[pkg-pr-new]

Open in Stackblitz

npm i https://pkg.pr.new/@vitejs/plugin-vue@486

npm i https://pkg.pr.new/@vitejs/plugin-vue-jsx@486

commit: 3f55553

[sapphi-red]

h2.hmr already contained HMR updated because it was updated at

vite-plugin-vue/playground/vue/__tests__/vue.spec.ts

Lines 175 to 176 in 3f55553

	editFile('Hmr.vue', (code) => code.replace('HMR', 'HMR updated'))
	await untilUpdated(() => page.textContent('h2.hmr'), 'HMR updated')

So this untilUpdated asserted nothing.

That made editFile('Hmr.vue' and editFile('Hmr.vue' to run almost the same time and caused the file-changed message to be sent in reverse order sometimes.
When the file-changed message is sent in reverse order, a renderer happens and thus the test fails.

[sapphi-red]

The CI passed five times in a row. I guess this change made it stable.