Fix semantic error for unsupported table INSERT time expressions

[hongzhi-gao]

Description

Fix table INSERT statements that use unsupported time expressions. They now return a semantic error instead of exposing a ClassCastException. Valid
timestamps and NULL keep their existing behavior.

The parser now uses the existing AstUtil.expressionToTimestamp method, so both insert paths apply the same validation. Integration tests cover supported
values, unsupported expressions, and prepared statements.

Validation: Spotless passed; Maven test-compile passed for all 39 modules. Integration tests were added but not run.

This PR has:

• been self-reviewed.
• added integration tests.

Key changed/added classes

• AstBuilder: delegates timestamp conversion to AstUtil.
• IoTDBInsertTableIT: covers supported and unsupported time values.
• IoTDBTablePreparedStatementIT: covers rejected time parameters.

[Caideyipi]

Reviewed the current head. No code issues found. The PR description still says the tests cover prepared statements, but that test was removed in the latest commit; please update the description to match the final diff.