Python CI runs ubuntu-latest, where WINPE_* and SYS_* constants collapse to the same path #796

Steps to Reproduce

1. Note that .github/workflows/python_tests.yml runs on ubuntu-latest.
2. On Linux, evaluate os.path.join('X:', os.sep, 'Windows', 'System32'). The drive letter is discarded.
3. Run testing/run_tests.py on Windows and compare drivers_test.test_driver_wim.

Expected Behavior

WINPE_SYSTEM32 and SYS_SYSTEM32 name different roots, so a test pinning the wrong one should fail.

Current Behavior

They render identically on the CI platform:

Any assertion pinning the wrong root passes there, so CI cannot tell the boot drive from the system drive.

drivers_test.test_driver_wim expects WINPE_DISM. winpe.check_winpe() is unmocked and returns False off WinPE, so the code builds SYS_DISM. On Linux both render /Windows/System32/dism.exe and it passes.

Notes

Windows 11, Python 3.13.13.

ntp.py:30 builds BINARY from WINPE_SYSTEM32 while ntp_test.py:52 asserts SYS_SYSTEM32, the same divergence. That one is currently unreachable on Windows: ntp_test.py:36 calls time.tzset(), which does not exist on win32, so the test errors before the assertion runs. If the assertion is right, SyncClockToNtp invokes X:\Windows\System32\cmd.exe, which is not present on a booted system.

go_tests.yml already runs windows-latest, so a Python leg is precedented. It would be red until these are settled.

Log/Screenshot

Expected: call('X:\Windows\System32\dism.exe', ...)
Actual:   call('C:\Windows\System32\dism.exe', ...)