NativeCrypto: adjust BasicConstraints check

OpenSSL checks KeyUsage for "Certificate Signing" when checking for a
CA, but Java just specifies that the getBasicConstraints call only looks
at the BasicConstraints itself.

(cherry picked from commit cd59afd3e34cb6b3645babdace22c03882e0ec19)

Bug: 8488314
Change-Id: I72f8d6679169480960630bd73745ebf4c55b383c
3 files changed