Skip UNC tests on AppVeyor in case of ENOENT (GH-1950)

diff --git a/Lib/test/test_tcl.py b/Lib/test/test_tcl.py
index 4c2e8d5..921d094 100644
--- a/Lib/test/test_tcl.py
+++ b/Lib/test/test_tcl.py
@@ -256,7 +256,7 @@
             try:
                 p = Popen(cmd, stdout=PIPE, stderr=PIPE)
             except WindowsError as e:
-                if e.winerror == 5:
+                if e.winerror == 5 or e.winerror == 2:
                     self.skipTest('Not permitted to start the child process')
                 else:
                     raise