dotnet format (latest 8) intermittently fails with "Unable to locate dotnet CLI. Ensure that it is on the PATH."

[christophwille]

Initially opened over at dotnet/format#2218 (forgot that it was moved...)

This started happening to our Github builds this weekend:

We never had any issues whatsoever, so initially we were looking at the newly installed net90, but then found microsoft/azure-pipelines-tasks#19162 (and by extension dotnet/format#2000). However, when locking to the latest version in https://github.com/icsharpcode/ILSpy/pull/3338/files we still see "Unable to locate dotnet CLI. Ensure that it is on the PATH.".

So it wasn't the old-ish version of dotnet-format that tripped us up but it happens also with the latest 8-series one. Any ideas/pointers where to start looking next? This flakiness is annoying (but not a showstopper atm).