fix(componentRenderUtils): a wrong judge in shouldUpdateComponent (#677)

[ysj16]

This PR is to fix #677, #677 can be more simple, the bug still exit without <transition-group>, there are two problems cause it.
I had resolved one, now #677 can patch text correctly.
About the color(class) patch error, I had found the reason. But I still have some confussion, I don't know what is the best way to fix it：In vue-next, a Component can have multi root element, so how to deal with class or style, all to inherit？
(I am not good at English.≥.≤)

[ysj16]

I found the warn just now.. I will try to fix the class patch error in this situation.
"vue.global.js:4748 [Vue warn]: Extraneous non-props attributes (class) were passed to component but could not be automatically inherited because component renders fragment or text root nodes."

[ysj16]

Done. @yyx990803

[yyx990803]

Thanks a lot for the PR - although it wasn't fully fixing the issue, it did help me identify the underlying problem faster.

See 6810d14 - we need to account for more possible merged attrs than just class or style. In addition, we should only attach/modify patchFlags when the child root is indeed an optimized node (indicated by the presence of dynamicChildren), otherwise we may cause it to bypass other necessary updates.

[ysj16]

Got it