Incremental global placement needs to be timing aware

Describe the bug

In https://github.com/The-OpenROAD-Project/OpenROAD/pull/11357 I changed the operation of gpl. In asap7/cva6 this results is a slightly different result which has the effect of going from 0 swaps to 3 swaps in replace_arith_modules. This ultimately degrades final timing.

The problem appears to originate from global_placement -incremental. It is not timing aware and undoes some of the previous optimization. Presumably routability suffers from a similar potential issue. It needs to have some timing awareness:

┌──────┬───────────────┬───────────┬───────────────────┬─────────────────┐
│      │ DP input HPWL │ legalized │ legalization cost │   TNS effect    │
├──────┼───────────────┼───────────┼───────────────────┼─────────────────┤
│ base │ 490,398       │ 523,270   │ +6.7%             │ improved 1,551  │
├──────┼───────────────┼───────────┼───────────────────┼─────────────────┤
│ new  │ 463,021       │ 499,186   │ +7.8%             │ degraded 23,324 │
└──────┴───────────────┴───────────┴───────────────────┴─────────────────┘

Additionally there is no ability to revert such a degradation so it is sticky.

Expected Behavior

No timing degradation from incremental placement.

Environment

https://content.jenkins.openroad.tools/static-files/MAnyA5HOjJbaxuGn-zvFklzYWemco1jWbAcG50yazfUxNzg4ODc4NTI2MzYxOjQ6bWF0dDpqb2IvT3BlblJPQUQtZmxvdy1zY3JpcHRzLVByaXZhdGUvam9iL3NlY3VyZS1ncGwtY29udmVyZ2VuY2UtZml4ZXMvMS9hcnRpZmFjdA==/final_report_cva6_asap7_base_2026-09-08_05-33.tar.gz

https://content.jenkins.openroad.tools/static-files/h9-GN95LeEJlKVQLwHHqasufJ39-arLOLq6u8h3hXmYxNzg4ODc4NTUzNDAxOjQ6bWF0dDp1c2VyL21hdHQvbXktdmlld3Mvdmlldy9NYXN0ZXIvam9iL09wZW5ST0FELWZsb3ctc2NyaXB0cy1OaWdodGx5LVB1YmxpYy83NDgxL2FydGlmYWN0/final_report_cva6_asap7_base_2026-09-08_08-24.tar.gz

To Reproduce

See above

Relevant log output

Screenshots

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Additional Context

No response