Tweak test data for one test case to not rely on mbedtls_asn1_get_int
lacking support for leading zeros. Instead, use a number that is
actually out of range for int.
Tweak test data for one test case to not rely on
mbedtls_asn1_get_bitstring_null rejecting bitstrings shorter than two
octets. Instead, try bit strings that are genuinely invalid, or have a
nonzero number of unused bits.
Add a test case with a correct empty signature. This is commented out
because asn1parse currently does not support this. Uncomment it when
asn1parse is updated to support this.
2dedcc5989