odb: ignore duplicated macros

[gadfort]

Summary

I was debugging something and noticed that if macros are read twice they merge. In other places we simply ignore duplicates, this add a warning and ensures we ignore the second read of the file.

Type of Change

• Bug fix

Impact

N/A

Verification

• I have verified that the local build succeeds (./etc/Build.sh).
• I have run the relevant tests and they pass.
• My code follows the repository's formatting guidelines.
• I have included tests to prevent regressions.
• I have signed my commits (DCO).

[gemini-code-assist]

Code Review

This pull request adds a check in lefinReader::macroBegin to ignore duplicate MACRO definitions when the master is already frozen, logging a warning instead of merging or overwriting. It also adds a dedicated test case and updates several existing test expectations to account for the new warning and the reduced library cell counts. There are no review comments, so no feedback is provided.