fix(computed): When no dependencies are passed in, computed does not use the cache #12857

[MKbird1]

<script setup>
import { reactive,computed } from 'vue'
const state = reactive({
  a: 1
})
const stateComputed = computed(() => {
  console.log('a')
  return 1
})
console.log(stateComputed.value)
state.a++
console.log(stateComputed.value)
</script>

expected output a 1 1

[skirtles-code]

I think this is attempting to solve the same problem as #12341.

I haven't looked at the differences between the two PRs in detail, so I don't know which fix is more correct.

@MKbird1 If you still want to proceed with this PR could you please add a test case? Bug fixes need to be accompanied by tests where possible. Thanks.

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	100 kB (+15 B)	38.1 kB (+2 B)	34.3 kB (+10 B)
vue.global.prod.js	158 kB (+15 B)	58 kB (+2 B)	51.6 kB (-59 B)

Usages

Name	Size	Gzip	Brotli
createApp (CAPI only)	46.5 kB (+15 B)	18.2 kB (+2 B)	16.7 kB (-5 B)
createApp	54.6 kB (+15 B)	21.3 kB (+1 B)	19.4 kB (+13 B)
createSSRApp	58.8 kB (+15 B)	23 kB (+2 B)	21 kB (+1 B)
defineCustomElement	59.4 kB (+15 B)	22.9 kB (+1 B)	20.8 kB (-13 B)
overall	68.6 kB (+15 B)	26.4 kB (+4 B)	24 kB

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commit: a66a776