Update mimalloc to v2.2.4

[dschuff]

This brings in general updates, as well as a revision (4aae566191b9443d53995245b637ce28d617710a)
needed to build on Windows.

[kripken]

Sounds good to update, but looks like Alpine is failing on that revision? Maybe we should wait for a stable release?

[dschuff]

I had thought that this was a stable release (the 2.2.3 tag).
The revision I pulled in was not actually the one I linked to, I just wanted to say why I was updating.
I will double check (GH really does not make it easy to tell exactly what the old a new revisions are for submodules).

[kleisauke]

The compilation failure on Alpine Linux ought to be fixed with commit microsoft/mimalloc@3411493, which is included in mimalloc v2.2.4 (microsoft/mimalloc@fbd8b99).

[dschuff]

Updated to 2.2.4. I don't think we necessarily need to have this (on emscripten-releases we've just updated the Linux build to use mimalloc because of a performance issue) but updating seems good in general.