ci: make build space cleanup faster

[shyim]

Before: 1minute 13s After: ~7s

[hsz]

What kind of sorcery is that?

[shyim]

See https://unix.stackexchange.com/a/79656 :)

[hsz]

What is interesting, it took 2m to execute that task: https://github.com/JetBrains/intellij-platform-plugin-template/actions/runs/5104089990/jobs/9239796367

[hsz]

I've tested that solution in other repositories, and it isn't stable. Rarely it takes ~10s, but for most cases, it takes ~2m. Given the more complicated syntax of the proposed solution, I'll stick to the current one. Anyways, thanks for contributing!