pythongh-109566: PCbuild/rt.bat now uses --fast-ci

Replace "--fail-env-changed --fail-rerun" with "--fast-ci".

Tools/buildbot/test.bat pass --slow-ci which has the priority over
--fast-ci.

Author: vstinner

PCbuild/rt.bat

@@ -32,7 +32,7 @@ set pcbuild=%~dp0
 set suffix=
 set qmode=
 set dashO=
-set regrtestargs=--fail-env-changed --fail-rerun
+set regrtestargs=--fast-ci
 set exe=
 
 :CheckOpts