Revert driver-vertex levelization (PR #327): move to OpenROAD/dbSta

[openroad-ci]

Summary

Reverts the driver-vertex levelization additions from PR #327 (commit 94bb37b). Functionality moves to OpenROAD's src/dbSta/ to keep this fork bit-for-bit compatible with upstream parallaxsw/OpenSTA and unblock building OpenROAD against upstream.

Background

PR #327 added Sta::levelizedDrvrVertices() + Levelize::levelizedDrvrVertices() cache + report_levelized_drvr_vertices Tcl helper. These don't exist upstream. OpenROAD's rsz/ calls
sta_->levelizedDrvrVertices() (where sta_ is sta::dbSta*), so building OpenROAD against upstream OpenSTA fails:
error: no member named 'levelizedDrvrVertices' in 'sta::Sta'

The companion OpenROAD PR https://github.com/The-OpenROAD-Project-private/OpenROAD/pull/3400 moves the implementation into dbSta using only public OpenSTA APIs (StaState::levelize(), LevelizeObserver), so existing rsz call sites resolve via inheritance (dbSta : public Sta) without source changes.

Changes

• include/sta/Sta.hh — drop levelizedDrvrVertices() decl
• search/Sta.cc — drop impl
• search/Levelize.{hh,cc} — drop public API, protected helper, cache members + invalidation in clear/invalid/deleteVertexBefore/relevelizeFrom/deleteEdgeBefore
• graph/Graph.i — drop report_levelized_drvr_vertices Tcl helper + search/Levelize.hh include
• test/regression_vars.tcl — drop levelized_drvr_vertices1 entry
• test/levelize_drvr_vertices1.{tcl,ok}, test/gcd_asap7.v — removed (relocated to OpenROAD dbSta/test/)

[gemini-code-assist]

Code Review

This pull request removes the levelizedDrvrVertices functionality and its associated reporting tools and regression tests from the codebase. This includes cleaning up the Sta and Levelize classes by removing the relevant methods and member variables. I have no feedback to provide.

[precisionmoon]

Thank you for taking care of this.

[maliberty]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Already looking forward to the next diff.

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