We need to add support to our CertPathBuilder implementation to find issuer certificates
using the caIssuer field of the AIA extension and HTTP URLs. We added CertPathBuilder impl.
support for the caIssuer field of the AIA extension as part of 6224160, but due to time
considerations only LDAP URLs are supported.

The NIST X509 Path Discovery Test Suite includes tests for HTTP URLs and is an excellent
way to test our implementation.