Replace the old JSX builder with the one that has been used experimentally

[Andarist]

Q	A
Fixed Issues?	N/A
Patch: Bug Fix?
Major: Breaking Change?
Minor: New Feature?
Tests Pass?	Yes
Documentation PR Link
Any Dependency Changes?
License	MIT

This is just a followup to #12253 . That other PR has switched over to using the -experimental package so the old one became completely unused. In this PR I have just removed the old & and unused builder and replaced it with the -experimental one.

[babel-bot]

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[Andarist]

I've missed that the old helper is still used by @babel/plugin-transform-react-jsx-compat and @babel/plugin-transform-react-inline-elements. It seems that this should be cleaned up at a later point in time because I'm not even sure if you want to keep supporting -compat transform.

[nicolo-ribaudo]

Yeah @babel/plugin-transform-react-jsx-compat has only 222 downloads/week, we can probably deprecate and archive it.

[Andarist]

It would probably be easiest to just drop it when releasing Babel 8. There were also tests failing for the @babel/plugin-transform-react-inline-elements but I don't have time to investigate this right now.