Sta latest from parallaxsw tidy 0416

[openroad-ci]

1. Removed "util/Machine.cc" from srcs (file deleted upstream).
2. Removed the 6-line commented-out select() block (dead code).
3. Replaced with a live select() on srcs covering all four platforms — mirrors CMakeLists.txt:241-249 exactly:
   - @platforms//os:osx → MachineApple.cc
   - @platforms//os:linux → MachineLinux.cc
   - @platforms//os:windows → MachineWin32.cc
   - //conditions:default → MachineUnknown.cc
4. Removed the textual_hdrs block that (wrongly) listed the platform files as text-include headers.

Net effect: Bazel should now compile exactly one platform-specific .cc into libOpenSTA.a, matching CMake. The previous Linux CI wasn't caught because macOS CI is the first to exercise a different branch of the
broken textual_hdrs select — but both platforms had the same underlying problem (nothing was actually compiled, only exposed as includable text for the missing dispatcher).

[dsengupta0628]

fixes macOS build issue as seen in OpenROAD: The-OpenROAD-Project/OpenROAD#10206