With the perl test framework comes the output format TAP
(Test Anything Protocol, see http://testanything.org/) with
extra extension for subtests. This change extends that same
output format to any test program using testutil.
In this implementation, each test program is seen as a full test that
can be used as a subtest. The perl framework passes on the subtest
level to the test programs with the environment variable
HARNESS_OSSL_LEVEL. Furthermore, and series of tests added with
ADD_ALL_TESTS is regarded as another subtest level.
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3296)
