py36+: remove TYPE_CHECKING from _pytest.compat

automated with:

```bash
git grep -l 'from .* import TYPE_CHECKING' |
    xargs reorder-python-imports \
        --application-directories .:src \
        --remove-import 'from _pytest.compat import TYPE_CHECKING' \
        --add-import 'from typing import TYPE_CHECKING'
```

testing/test_junitxml.py

@@ -4,13 +4,13 @@ from datetime import datetime
 from typing import cast
 from typing import List
 from typing import Tuple
+from typing import TYPE_CHECKING
 from xml.dom import minidom
 
 import py
 import xmlschema
 
 import pytest
-from _pytest.compat import TYPE_CHECKING
 from _pytest.config import Config
 from _pytest.junitxml import bin_xml_escape
 from _pytest.junitxml import LogXML