Do not skip Tkinter tests for ASAN builds if not using X11

[chrstphrchvz]

Feature or enhancement

gh-30897 skips Tkinter tests for AddressSanitizer builds due to libX11-related errors. I have not located the discussion for these errors, but I do not believe this skipping should be done for Tk on Win32 or Aqua windowing systems, as they do not use actual libX11.

I am not aware of a good way to detect the windowing system without loading Tk. Is it okay to load Tk to detect the windowing system before deciding whether to skip?