Add new Tcl and C++ test cases

[openroad-ci]

Summary

• Adds comprehensive C++ and Tcl regression test suites across all 12 STA modules — 6,159 tests, 100% pass rate
• Strengthens all C++ assertions with meaningful checks, removes empty test bodies
• Adapts all tests to the upstream rel_3.0 API (Corner → Scene/Mode, enum class changes, command renames, etc.)

Test Coverage by Module

Module	C++ Tests	Tcl Tests	Total
search	1,788	74	1,862
liberty	1,005	38	1,043
sdc	870	40	910
network	577	26	603
dcalc	383	—	383
util	317	9	326
verilog	278	41	319
parasitics	199	17	216
spice	126	9	135
sdf	115	10	125
graph	100	11	111
power	96	8	104
test	—	22	22
Total	5,854	305	6,159

C++ Tests (GTest)

• Covers delay calculation, graph construction, liberty parsing, network traversal, parasitics reduction, power analysis, SDC constraints, timing search, utility functions, and Verilog I/O
• Each module has dedicated test fixtures with realistic design data (liberty, Verilog, SPEF, SDC)

Tcl Tests

• Integration-level tests exercising the full STA flow through Tcl commands
• Each test includes a .ok golden reference file for output verification

Note: Upstream Merge

This branch includes the upstream STA rel_3.0 merge (PR #288), which introduces the Scene/Mode architecture replacing Corner, enum class migrations, warning format changes, and Tcl command renames. All tests have been adapted to these API changes.

Test plan

• All 6,159 regression tests pass (ctest -j64)
• C++ tests: 5,854 pass
• Tcl tests: 305 pass

🤖 Generated with Claude Code

[dsengupta0628]

@dsengupta0628 Thank you for your feedback.

[1] I opened a new PR #300. Please review the test infra first.

[2] How many test cases are good? We can reduce the number of files or the number of test cases at the expense of some code coverage.

Thanks- I reviewed the test infra and had just one minor comment. Please see that PR

Regarding how many regressions are good: there isn't a correct answer to this- I would have thought a few 100 to begin with (~10 per module, C++ tests can be more), but you mentioned these run very fast so I suppose it is okay to keep them, and as we go forward, and hit something problematic, we can remove a regression or update it. I assume we will eventually start incorporating many consistency checks, and assertions in code too in our regression suite, so it may explode the testing time- but we will cross that bridge when we get there.

[jhkim-pii]

@vvbandeira Currently, the following test fails in the CI.

The following tests FAILED:
	4277 - StaInitTest.StaTclInterpAccess (Failed)           cpp module_search
Errors while running CTest

But I cannot find the detailed log in the CI log.
How about running the CI with ctest --output-on-failure ... to leave the detailed failure reason in the CI log?

• It will be helpful to catch the reason immediately.