TEMP vs Temp

[bramtayl]

CI seems to be broken on Windows due to the capitalization of the TEMP folder. See e.g.

https://build.julialang.org/#/builders/32/builds/8615/steps/3/logs/stdio
https://build.julialang.org/#/builders/65/builds/8232/steps/3/logs/stdio

Seems like it might be an issue with realpath?

[KristofferC]

Rebase the branch so it includes #34506

[bramtayl]

Oops. Thanks!