Fix a race condition in parallel builds: when generating *.data files with
generate_psa_tests.py, make instantiated the recipe once per output file,
potentially resulting in multiple instances of generate_psa_tests.py running
in parallel. This not only was inefficient, but occasionally caused the
output to be corrupted (https://github.com/ARMmbed/mbedtls/issues/4773). Fix
this by ensuring the recipe only runs once.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
5df77c63fb