re-add quick check for alternative engineering database test

The test_environmental test when not run on the vpn
will fail to contact the alternative engineering database
server. This results in the test taking ~10 minutes waiting
for a response before turning into a skip.

This commit adds some lines of code that were removed in
PR #3022 which changed the skip from a decorator to a
pytest.skip when the exception/timeout occurs. This should
allow the test to skip quickly when the host is not accessable
(and instead skips in <1 second). The pytest.skip call
during the except block is left to deal with cases when the
host resolves but the url fails to resolve.

jwst/lib/tests/test_engdb_tools.py

@@ -62,6 +62,10 @@ def engdb():
         yield engdb
 
 
+@pytest.mark.skipif(
+    not is_alive(ALTERNATE_HOST),
+    reason='Alternate test host not available.'
+)
 def test_environmental(jail_environ):
     os.environ['ENG_BASE_URL'] = ALTERNATE_URL
     try: