feat: support usage of `v-once` with `v-if`

[lulu0119]

Implemented basic v-once support for v-if/else via a once flag, please review and advise if any scenarios are unaddressed.

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Size Report

Bundles

File	Size	Gzip	Brotli
compiler-dom.global.prod.js	80 kB	28.1 kB	24.7 kB
compiler-vapor.global.prod.js	55.5 kB (+60 B)	18.9 kB (+12 B)	17.1 kB (+37 B)
runtime-dom.global.prod.js	96.6 kB	36.5 kB	32.9 kB
runtime-vapor.global.prod.js	45.2 kB (+23 B)	16.9 kB (+32 B)	15.5 kB (+28 B)
vue-vapor.global.prod.js	97.9 kB (+83 B)	34.3 kB (+53 B)	30.9 kB (-2 B)
vue.global.prod.js	154 kB	55.8 kB	49.8 kB

Usages

Name	Size	Gzip	Brotli
createApp	57 kB	21.9 kB	20 kB
createSSRApp	60.4 kB	23.3 kB	21.2 kB
defineCustomElement	59.3 kB	22.7 kB	20.7 kB
vapor	45.6 kB (+23 B)	16.9 kB (+25 B)	15.5 kB (+24 B)
overall	70.7 kB	26.9 kB	24.4 kB

[lulu0119]

Thank you, sxzz, for helping me with the modifications.