build,tools,win: trim unused VCBUILD_PYTHON_LOCATION variable

PR-URL: #41235
Refs: #18621
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>

tools/msvs/find_python.cmd

@@ -49,7 +49,6 @@ echo Python found in %p%\python.exe
 endlocal ^
   & set "pt=%p%" ^
   & set "need_path_ext=%need_path%"
-set "VCBUILD_PYTHON_LOCATION=%pt%\python.exe"
 if %need_path_ext%==1 set "PATH=%pt%;%PATH%"
 set "pt="
 set "need_path_ext="