Fix tox4 error

tox.ini started failing with Tox4 which had some
incompatible changes. One is passenv where we need
to pass each value in newline otherwise, it fails with
error:

 failed with pass_env values cannot contain whitespace,
 use comma to have multiple values in a single line,
 invalid values found.....

Fixing tox.ini for tox4 changes.

Also, remove the stable/rocky|stein job as they are
in EM state and jobs are failing.

Change-Id: Idfa3c5aab012cf8381e001d4c3018b92b76f89af

.zuul.yaml

@@ -64,10 +64,6 @@
             - ^.gitreview$
       - tempest-full-train:
           irrelevant-files: *irrelevant-files
-      - tempest-full-stein:
-          irrelevant-files: *irrelevant-files
-      - tempest-full-rocky:
-          irrelevant-files: *irrelevant-files
     gate:
       jobs:
       - openstack-tox-pep8

tox.ini

@@ -13,7 +13,19 @@ setenv =
     OS_STDOUT_CAPTURE=1
     OS_STDERR_CAPTURE=1
     OS_TEST_TIMEOUT=160
-passenv = OS_STDOUT_CAPTURE OS_STDERR_CAPTURE OS_TEST_TIMEOUT OS_TEST_LOCK_PATH http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY ZUUL_CACHE_DIR REQUIREMENTS_PIP_LOCATION
+passenv =
+    OS_STDOUT_CAPTURE
+    OS_STDERR_CAPTURE
+    OS_TEST_TIMEOUT
+    OS_TEST_LOCK_PATH
+    http_proxy
+    HTTP_PROXY
+    https_proxy
+    HTTPS_PROXY
+    no_proxy
+    NO_PROXY
+    ZUUL_CACHE_DIR
+    REQUIREMENTS_PIP_LOCATION
 usedevelop = True
 install_command = pip install -U {opts} {packages}
 allowlist_externals = *