Revert fix-macos-pytest (#5853)

* Revert "Fix pytest on macOS in Travis (#5360)"

This reverts commit 5388842e5b.

* remove oldest passenv

tools/install_and_test.sh

@@ -19,5 +19,5 @@ for requirement in "$@" ; do
   if [ $pkg = "." ]; then
     pkg="certbot"
   fi
-  "$(dirname $0)/pytest.sh" --pyargs $pkg
+  pytest --numprocesses auto --quiet --pyargs $pkg
 done

tools/pytest.sh

@@ -1,15 +0,0 @@
-#!/bin/bash
-# Runs pytest with the provided arguments, adding --numprocesses to the command
-# line. This argument is set to "auto" if the environmnent variable TRAVIS is
-# not set, otherwise, it is set to 2. This works around
-# https://github.com/pytest-dev/pytest-xdist/issues/9. Currently every Travis
-# environnment provides two cores. See
-# https://docs.travis-ci.com/user/reference/overview/#Virtualization-environments.
-
-if ${TRAVIS:-false}; then
-    NUMPROCESSES="2"
-else
-    NUMPROCESSES="auto"
-fi
-
-pytest --numprocesses "$NUMPROCESSES" "$@"