Windows runners fail sporadically during conda tests

Example of a failed job here.

The Windows test runners will fail occasionally when running the tests. They usually fail on a PR run when all the windows runners are run at once, and re-running each individually tends to work out okay.

It seems to always fail on one of the conda environment tests.

The specific failure is a Windows OS error:

make[1]: *** [Makefile:17: requirements] Error -1073741819

This appears to be a Windows file system error.