修复了select组件placeholder溢出的问题

[yeliex]

#2453

• Make sure you follow antd's code convention.
• Run npm run lint and fix those errors before submitting in order to keep consistent code style.
• Rebase before creating a PR to keep commit history clear.
• Add some descriptions and refer relative issues for you PR.

[mention-bot]

@yeliex, thanks for your PR! By analyzing the annotation information on this pull request, we identified @afc163, @warmhug and @yiminghe to be potential reviewers