Add test cases for datetime cast function

[zyfy29]

Issue partiql/partiql-lang-kotlin#1734

Description of changes:

add eval test cases for string to datetime cast function, contains

• date
• time
• time with time zone
• timestamp
• timestamp with time zone

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[Copilot]

Pull Request Overview

Adds comprehensive test coverage for string to datetime cast functions including both valid and invalid casting scenarios for various datetime types.

• Adds valid cast test cases for DATE, TIME, TIME WITH TIME ZONE, TIMESTAMP, and TIMESTAMP WITH TIME ZONE
• Adds invalid cast test cases that attempt to cast datetime strings to INT type
• Verifies proper behavior in both EvalModeCoerce and EvalModeError modes

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