rt.bat: use -m test instead of Lib\test\regrtest.py
diff --git a/PCbuild/rt.bat b/PCbuild/rt.bat
index 2d93b80..7d4d071 100644
--- a/PCbuild/rt.bat
+++ b/PCbuild/rt.bat
@@ -42,7 +42,7 @@
if NOT "%1"=="" (set regrtestargs=%regrtestargs% %1) & shift & goto CheckOpts
set exe=%prefix%python%suffix%.exe
-set cmd="%exe%" %dashO% -Wd -E -bb "%pcbuild%..\lib\test\regrtest.py" %regrtestargs%
+set cmd="%exe%" %dashO% -Wd -E -bb -m test %regrtestargs%
if defined qmode goto Qmode
echo Deleting .pyc/.pyo files ...