Since the code is identical when just checking if a utility is present on
the system or not, we can factorize it.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
With these changes, "make sc_prohibit_test_minus_ao" almost passes.
Uses of "test -o" remain.
Note: unchecked uses of test -ot/-nt also remain.
* tests/empty-files: Use "test C1 && test C2", not "test C1 -a C2"
* tests/merge: Likewise.
* tests/symlinks: Likewise.
* tests/test-lib.sh: Likewise.
