test1134: verify CREDSPERREQUEST for HTTP

Verifies that the change in 68f0166a92 works as intended and that
different HTTP auth credentials to the same host still re-uses the
connection properly.
test1014: GSS-API is only in curl-config. not in curl

Follow-up to commit 121bcfee5d1. curl-config --features now lists
GSS-API but it is not a listed feature in curl -V. This should probably
be synchronized.