FAPI TEST: rework test certificate creation #527

Job	Run time
coverity-test	0s
scanbuild	6m 30s
test-coverage	4m 51s
build-test (ubuntu-18.04, gcc)	4m 19s
test-fuzz	2m 37s
build-test (ubuntu-18.04, clang)	4m 52s
test-mbedtls (ubuntu-20.04)	3m 0s
build-test (ubuntu-20.04, gcc)	4m 37s
test-no-crypto-build	1m 18s
test-mbedtls (ubuntu-22.04-mbedtls-3.1)	2m 51s
build-test (ubuntu-20.04, clang)	4m 21s
test-tcti-config	14m 0s
build-test (fedora-32, gcc)	4m 38s
build-test (fedora-32, clang)	4m 59s
build-test (opensuse-leap, gcc)	4m 25s
build-test (opensuse-leap, clang)	4m 31s
build-test (ubuntu-22.04, gcc)	4m 27s
build-test (ubuntu-22.04, clang)	4m 37s
build-test (alpine-3.15, gcc)	3m 49s
build-test (alpine-3.15, clang)	4m 53s
	1h 29m 35s

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