tests: Add basic test for OrderedDict.

Mostly to have coverage of newly added code in map.c.

tests/basics/ordereddict1.py

@@ -0,0 +1,16 @@
+try:
+    from collections import OrderedDict
+except ImportError:
+    try:
+        from _collections import OrderedDict
+    except ImportError:
+        print("SKIP")
+        import sys
+        sys.exit()
+
+d = OrderedDict([(10, 20), ("b", 100), (1, 2)])
+print(list(d.keys()))
+print(list(d.values()))
+del d["b"]
+print(list(d.keys()))
+print(list(d.values()))