Start refactor to provider check for emit instead of SCU Consum…

[JoviDeCroock]

I've started this but will probably be getting back to it next week, Bad news I've found a potential stale dom issue with the SCU I've added in the tests

Fixes #1933

EDIT: Add list of resolved issues - @marvinhagemeister

[coveralls]

Coverage increased (+0.1%) to 99.882% when pulling 6d88906 on feat/checkForNeedToEmit into 8c6ac43 on master.

[mxstbr]

Note to readers, here is the most minimal reproduction of the issue: https://codesandbox.io/s/double-context-preventing-value-propagation-rj00e

[cristianbote]

Hey @mxstbr thanks for the sandbox. The thing is, that with master that works. Got merged in here https://github.com/preactjs/preact/pull/1925/files#diff-e959fc84d230f763daeb8f8fa0a571e7R18. Is there another case where this breaks?

[mxstbr]

I am running the latest master in our project locally and it is definitely still broken. Here is the slightly-less-minimal reproduction that I sent @JoviDeCroock privately: https://codesandbox.io/s/issue-1864-urv9j

[marvinhagemeister]

Looking good here👍

[atcq-me]

Hi, should this pull request fix issue #1933?

[marvinhagemeister]

@Nuzsk Just checked the repro in the linked issue with the changes in this PR and it fixes the issue for me. The popup appears as expected with this PR 👍

[marvinhagemeister]

Just checked all issues that relate to this that I know of and the changes here resolve them. In my opinion this PR is ready to be merged 💯

[JoviDeCroock]

Thank you so much for taking this up @cristianbote! Hero

[marvinhagemeister]

Let-a-go 🍄 👍