Fixed JSON validation, which was not taking order into account (backport of !1496)

I want to backport !1496 (merged) to v36-patches as I believe some of the test failures observed in LHCb sanitizers builds are caused by changes in the order of JSON dumps of counters and in that nightly builds slot LHCb still uses Gaudi v36.

See !1496 (merged) for details.

GaudiPolicy/python/GaudiTesting/BaseTest.py

@@ -1485,6 +1485,11 @@ class JSONOutputValidator:
 
         # piggyback on TestCase dict diff report
         t = TestCase()
+        # sort both lists (these are list of entities) as the order is not supposed to matter
+        # indeed, the JSONSink implementation does not garantee any particular order
+        # but as JSON does not have sets, we get back a sorted list here
+        expected = sorted(expected, key=lambda item: (item["component"], item["name"]))
+        out = sorted(out, key=lambda item: (item["component"], item["name"]))
         try:
             t.assertEqual(expected, out)
         except AssertionError as err: