Test SPNEGO acceptor response to MS krb5 mech OID

In t_spnego.c, add code to make a SPNEGO request with the erroneous
Microsoft OID value and examine the response to make sure that it uses
the same OID value as the request did.  The token and tmp variables
were unused, so rename them to itok and atok for the purpose of the
new test code.

(cherry picked from commit 53cfb8327c452bd72a8e915338fb5ec838079cd3)

https://github.com/krb5/krb5/commit/292b7807bab19d917caa13860da5bae3738f80c6
Author: Greg Hudson <ghudson@mit.edu>
Committer: Tom Yu <tlyu@mit.edu>
Commit: 292b7807bab19d917caa13860da5bae3738f80c6
Branch: krb5-1.12
 src/tests/gssapi/t_spnego.c |   64 ++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 60 insertions(+), 4 deletions(-)