[1.8.x] Sorted imports with isort; refs #23860.

Backport of 0ed7d15563 from master

tests/template_backends/test_jinja2.py

@@ -3,9 +3,10 @@
 from __future__ import absolute_import
 
 import sys
-
 from unittest import skipIf
 
+from .test_dummy import TemplateStringsTests
+
 # Jinja2 doesn't run on Python 3.2 because it uses u-prefixed unicode strings.
 if sys.version_info[:2] == (2, 7) or sys.version_info[:2] >= (3, 3):
     try:
@@ -19,8 +20,6 @@ else:
     jinja2 = None
     Jinja2 = None
 
-from .test_dummy import TemplateStringsTests
-
 
 @skipIf(jinja2 is None, "this test requires jinja2")
 class Jinja2Tests(TemplateStringsTests):