Move HEAD assignment for SSR compatibility (assembler)

[peremp]

When you import an SFC on Nuxt, it throws the following error even if the Component is SSR ready:
Reason: ReferenceError: document is not defined

This error is fixed by moving this

vue-component-compiler/src/assembler.ts

Line 91 in c4bcd40

const head = document.head || document.getElementsByTagName('head')[0]

inside the addStyle function

vue-component-compiler/src/assembler.ts

Line 97 in c4bcd40

return function addStyle(id, css) {

I cannot see any drawback of doing that, but you know better than me so, could that be done?