pytest: improvements for suitable curl and error output

- will check built curl for http and https support and
  skip all tests if not there
- will dump stdout/stderr/trace output on errored responses

Closes #10829

tests/http/test_09_push.py

@@ -34,8 +34,6 @@ from testenv import Env, CurlClient
 log = logging.getLogger(__name__)
 
 
-@pytest.mark.skipif(condition=Env.setup_incomplete(),
-                    reason=f"missing: {Env.incomplete_reason()}")
 class TestPush:
 
     @pytest.fixture(autouse=True, scope='class')
@@ -68,7 +66,7 @@ class TestPush:
         url = f'https://{env.domain1}:{env.https_port}/push/data1'
         r = curl.http_download(urls=[url], alpn_proto='h2', with_stats=False,
                                with_headers=True)
-        assert r.exit_code == 0, f'{r}'
+        r.check_exit_code(0)  
         assert len(r.responses) == 2, f'{r.responses}'
         assert r.responses[0]['status'] == 103, f'{r.responses}'
         assert 'link' in r.responses[0]['header'], f'{r.responses[0]}'