Regression on graph containing freeze node

[QilongTang]

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Purpose

The first graph in regression suits containing freeze node causing problem for regression. The code always assume node always have port value which is apparently not true..

Declarations

Check these if you believe they are true

• The code base is in a better state after this PR
• Is documented according to the standards
• The level of testing this PR includes is appropriate
• User facing strings, if any, are extracted into *.resx files
• All tests pass using the self-service CI.
• Snapshot of UI changes, if any.
• Changes to the API follow Semantic Versioning, and are documented in the API Changes document.

Reviewers

FYIs

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