Improve test coverage for TLS resume

[wfurt]

fix for #75079 did not have test as I was unable to construct one.
But in general, most tests do verify given behavior once but that may not be sufficient.
The behavior may change because of

• session cache (primarily windows)
• TLS resume (primarily Linux)

we should add test for #75079 as well as improve test coverage in general.

[ghost]

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Issue Details

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fix for #75079 did not have test as I was unable to construct one.
But in general, most tests do verify given behavior once but that may not be sufficient.
The behavior may change because of

• session cache (primarily windows)
• TLS resume (primarily Linux)

we should add test for #75079 as well as improve test coverage in general.

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

[rzikm]

Triage:

• Look at the coverage we already have and see if something is missing
• consider adding tests that check if a session was actually resumed, there is a Debug-only property which we can check via Reflection.

[rzikm]

Test covering #75079 was added as part of #79898, since then, multiple other changes have explicitly added checks with TLS resume as well, e.g. #86047. I don't think there are any missing tests at this point.