mpl: add new command set_macro_default_halo

[AcKoucher]

Summary

Apart from the title:

• Add 2 tests for the new command (2 - width, height - and 4 - L, B, R, T - halo arguments);
• Update existing tests to not use halos at all.
• Add deprecated warning for -halo_width and -halo_height.

Type of Change

• New feature

Impact

Setting a default halo is now possible without necessarily having to run MPL. That way, the blockage generation pass that is being developed will not rely on running MPL to cache the default halo data.

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 signed my commits (DCO).

[gemini-code-assist]

Code Review

This pull request refactors the macro halo configuration by replacing the global -halo_width and -halo_height arguments in rtl_macro_placer with a new, more flexible set_macro_default_halo command. This change allows for both uniform and per-side halo definitions. The reviewer suggested improving the Tcl command argument description for better user guidance.

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[AcKoucher]

Checks failures are due to bazel-orfs not containing the script changes on The-OpenROAD-Project/OpenROAD-flow-scripts#4149.

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"