Additional exec spec tests for command-not-found.
Additional exec spec tests for command-not-found.

(The chroot executor already passes these, but they're good to test because there are often different syscalls as the root "cause" of errors in this area.)

Signed-off-by: Eric Myhre <2346ad27d7568ba9896f1b7da6b5991251debdf2@exultant.us>

polydawn/repeatr,subuser-security/repeatr,polydawn/repeatr,subuser-security/repeatr