Remove enum tests for old python versions

- Getting `raise TApplicationException(TApplicationException.MISSING_RESULT, "testEnum failed: unknown result"` error
- PR#2825 state it is a breaking change, not sure why and for what version of Python

Author: CJCombrink

test/py/RunClientServer.py

@@ -278,7 +278,10 @@ def main():
     generated_dirs = []
     for gp_dir in options.genpydirs.split(','):
         if gp_dir == 'type_hints' and (sys.version_info < (3,7)):
-            print('Skipping \'type_hints\' test since python 3.6 or later is required')
+            print('Skipping \'type_hints\' test since python 3.7 or later is required')
+            continue
+        if gp_dir == 'enum' and (sys.version_info < (3,7)):
+            print('Skipping \'enum\' test since python 3.7 or later is required')
             continue
         generated_dirs.append('gen-py-%s' % (gp_dir))