Remove no longer necessary test ignore logic

Author: timothycrosley

tests/conftest.py

@@ -2,11 +2,3 @@
 import sys
 
 from .fixtures import *
-
-collect_ignore = []
-
-if sys.version_info < (3, 5):
-    collect_ignore.append("test_async.py")
-
-if sys.version_info < (3, 4):
-    collect_ignore.append("test_coroutines.py")