Changed sort_json test to test str sorting

Tests when simplejson was installed were failing because of a change in
how it sorted in v3.0.0. This change first tests it via normal int
sorting for stdlib json then if that fails, it tests against str sorting
for simplejson.

flask/testsuite/helpers.py

@@ -173,7 +173,33 @@ class JSONTestCase(FlaskTestCase):
         c = app.test_client()
         rv = c.get('/')
         lines = [x.strip() for x in rv.data.strip().decode('utf-8').splitlines()]
-        self.assert_equal(lines, [
+        sorted_by_str = [
+            '{',
+            '"values": {',
+            '"0": "foo",',
+            '"1": "foo",',
+            '"10": "foo",',
+            '"11": "foo",',
+            '"12": "foo",',
+            '"13": "foo",',
+            '"14": "foo",',
+            '"15": "foo",',
+            '"16": "foo",',
+            '"17": "foo",',
+            '"18": "foo",',
+            '"19": "foo",',
+            '"2": "foo",',
+            '"3": "foo",',
+            '"4": "foo",',
+            '"5": "foo",',
+            '"6": "foo",',
+            '"7": "foo",',
+            '"8": "foo",',
+            '"9": "foo"',
+            '}',
+            '}'
+        ]
+        sorted_by_int = [
             '{',
             '"values": {',
             '"0": "foo",',
@@ -198,8 +224,12 @@ class JSONTestCase(FlaskTestCase):
             '"19": "foo"',
             '}',
             '}'
-        ])
+        ]
 
+        try:
+            self.assert_equal(lines, sorted_by_int)
+        except AssertionError:
+            self.assert_equal(lines, sorted_by_str)
 
 class SendfileTestCase(FlaskTestCase):