Remove selftest dependency in the test suite

The test suites should always run self-tests for all enabled features.
Otherwise we miss failing self-tests in CI runs, because we don't
always run the selftest program independently.

There was one spurious dependency to remove:
MBEDTLS_CTR_DRBG_USE_128_BIT_KEY for ctr_drbg, which was broken but
has now been fixed.

tests/suites/test_suite_ctr_drbg.data

@@ -1097,6 +1097,4 @@ CTR_DRBG Special Behaviours
 ctr_drbg_special_behaviours:
 
 CTR_DRBG self test
-depends_on:!MBEDTLS_CTR_DRBG_USE_128_BIT_KEY
 ctr_drbg_selftest:
-