test: Apply review feedback - part2

- Remove stale line-number coverage comments (# Targets: line NNN, hit=0)
- Remove useless file-existence checks from verilog/sdf tests
- Delete 21 orphaned dcalc Tcl tests (C++ tests already cover them)
- Rename liberty_ccsn_ecsm -> liberty_ccsn (no ECSM libs available)
- Fix liberty_sky130_corners to use define_corners/-corner for real multi-corner testing
- Add report_checks per wireload model in liberty_wireload
- Fix test/regression to work from test/ directory (label mismatch)
- Refactor all module CMakeLists.txt with sta_module_tests() macro

Co-Authored-By: Claude Opus 4.6 <[email protected]>

test/regression

@@ -42,4 +42,10 @@ for arg in "$@"; do
 done
 
 cd "${build_dir}"
-ctest -L "module_${module}" "${args[@]}"
+
+# The top-level test/ directory uses label "tcl" (not "module_test").
+if [ "$module" = "test" ]; then
+  ctest -L "tcl" "${args[@]}"
+else
+  ctest -L "module_${module}" "${args[@]}"
+fi