Fix for Python 4: replace unsafe PY3 with PY2 (#5820)

Fix for Python 4: replace unsafe PY3 with PY2

Author: nicoddemus

testing/test_pdb.py

@@ -853,7 +853,7 @@ def test_supports_breakpoint_module_global(self):
         Test that supports breakpoint global marks on Python 3.7+ and not on
         CPython 3.5, 2.7
         """
-        if sys.version_info.major == 3 and sys.version_info.minor >= 7:
+        if sys.version_info >= (3, 7):
             assert SUPPORTS_BREAKPOINT_BUILTIN is True
         if sys.version_info.major == 3 and sys.version_info.minor == 5:
             assert SUPPORTS_BREAKPOINT_BUILTIN is False