test: bump the timeout for test-execute subtests if running w/ QEMU

test: bump the timeout for test-execute subtests if running w/ QEMU

Bump the timeout for test-execute subtests if running with plain QEMU
(as part of TEST-02-UNITTESTS), since we might start hitting the default
2m timeout with some more involved subtests, especially when the AWS
region we're running in is under heavy load. I see this regularly in the
CentOS Stream 9 nightly cron job with exec-dynamicuser-statedir.service
which has a lot of ExecStart's.