bpo-38183: Test_idle ignores user config directory GH-16198)

It no longer tries to create or access .idlerc or any files within.
Users must run IDLE to discover problems with saving settings.
diff --git a/Lib/idlelib/pyshell.py b/Lib/idlelib/pyshell.py
index 08716a9..2e4dfad 100755
--- a/Lib/idlelib/pyshell.py
+++ b/Lib/idlelib/pyshell.py
@@ -133,6 +133,7 @@
         self.text.bind("<<clear-breakpoint-here>>", self.clear_breakpoint_here)
         self.text.bind("<<open-python-shell>>", self.flist.open_shell)
 
+        #TODO: don't read/write this from/to .idlerc when testing
         self.breakpointPath = os.path.join(
                 idleConf.userdir, 'breakpoints.lst')
         # whenever a file is changed, restore breakpoints