Fix OCSP test responder to omit fractional seconds

[vcsjones]

Closes#77408

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Issue Details

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Closes #77408

Author:	vcsjones
Assignees:	-
Labels:	area-System.Security
Milestone:	-

[vcsjones]

/azp run runtime-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[vcsjones]

Doh. That was the wrong outerloop.

/azp run runtime-libraries-coreclr outerloop

[vcsjones]

/azp run runtime-libraries-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[vcsjones]

S.S.Cryptography outerloop passed. None of the outerloop failures appear related, and this is a test only change. Merging.

[vcsjones]

@bartonjs should this test-only change be back ported to release/7.0 or release/6.0 so that if/when those pick up Ventura the tests won't start failing?

[bartonjs]

Your question has certainly sold me on the value of the backport; and test-only changes are generally taken. So, yes 😄

[vcsjones]

/backport to release/7.0

[github-actions]

Started backporting to release/7.0: https://github.com/dotnet/runtime/actions/runs/3322798204

[vcsjones]

/backport to release/6.0

[github-actions]

Started backporting to release/6.0: https://github.com/dotnet/runtime/actions/runs/3322799106