Enhance the NTLM negotiation testing on Linux/macOS

[filipnavara]

Both krb5+gssntlm-ssp and macOS GSSAPI seem to support passing a custom credential file for testing through the NTLM_USER_FILE environment variable. The format of the file is the following:

DOMAIN:user:password

In theory that could enable some round-trip tests like the ones for HTTP authentication or the NegotiateStream tests. I briefly experimented with it and already uncovered a couple of issues.

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Issue Details

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Both krb5+gssntlm-ssp and macOS GSSAPI seem to support passing a custom credential file for testing through the NTLM_USER_FILE environment variable. The format of the file is the following:

DOMAIN:user:password

In theory that could enable some round-trip tests like the ones for HTTP authentication or the NegotiateStream tests. I briefly experimented with it and already uncovered a couple of issues.

Author:	filipnavara
Assignees:	-
Labels:	area-System.Net.Security
Milestone:	-