fix(runtime-core): check extends render when convertLegacyRenderFn (#6860)

[weidehai]

fix #6860

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	100 kB	38 kB	34.2 kB
vue.global.prod.js	159 kB	57.9 kB	51.4 kB

Usages

Name	Size	Gzip	Brotli
createApp (CAPI only)	46.9 kB	18.3 kB	16.7 kB
createApp	55 kB	21.3 kB	19.4 kB
createSSRApp	59 kB	23 kB	20.9 kB
defineCustomElement	59.8 kB	22.8 kB	20.8 kB
overall	68.7 kB	26.3 kB	24 kB

[pkg-pr-new]

Open in Stackblitz

@vue/compiler-core

pnpm add https://pkg.pr.new/@vue/compiler-core@6877

@vue/compiler-dom

pnpm add https://pkg.pr.new/@vue/compiler-dom@6877

@vue/compiler-ssr

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@vue/reactivity

pnpm add https://pkg.pr.new/@vue/reactivity@6877

@vue/runtime-core

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@vue/runtime-dom

pnpm add https://pkg.pr.new/@vue/runtime-dom@6877

@vue/server-renderer

pnpm add https://pkg.pr.new/@vue/server-renderer@6877

@vue/shared

pnpm add https://pkg.pr.new/@vue/shared@6877

@vue/compiler-sfc

pnpm add https://pkg.pr.new/@vue/compiler-sfc@6877

vue

pnpm add https://pkg.pr.new/vue@6877

@vue/compat

pnpm add https://pkg.pr.new/@vue/compat@6877

commit: 39c23bb