Fix Windows CI failures. #3227

Job	Run time
ubuntu-latest [CC gcc; botan; shared libs on; GnuPG stable]	4m 59s
ubuntu-latest [CC clang; botan; shared libs on; GnuPG stable]	3m 51s
ubuntu-latest [CC gcc; openssl; shared libs on; GnuPG stable]	4m 48s
ubuntu-latest [CC clang; openssl; shared libs on; GnuPG stable]	4m 25s
ubuntu-20.04 [CC gcc; openssl; shared libs on; GnuPG stable]	3m 56s
ubuntu-latest [CC gcc; botan; shared libs off; GnuPG stable]	4m 10s
cmake-offline-googletest	2m 24s
cmake-offline-googletest-src	2m 27s
system-sexpp, sexpp shared libs on, rnp shared libs on	2m 52s
system-sexpp, sexpp shared libs on, rnp shared libs off	2m 37s
system-sexpp, sexpp shared libs off, rnp shared libs on	2m 44s
system-sexpp, sexpp shared libs off, rnp shared libs off	1m 54s
package-source	34s
package	49s
debian-tests	11s
	42m 41s

Provide feedback