tests/comprehension1, containment: Split set tests to separate files.

To make skippable.

tests/basics/comprehension1.py

@@ -14,7 +14,6 @@ def f():
     print(d[0], d[1], d[2], d[3], d[4])
 
     # set comprehension
-
-    print({a for a in range(5)})
+    # see set_comprehension.py
 
 f()

tests/basics/containment.py

+# sets, see set_containment
 for i in 1, 2:
-    for o in {1:2}, {1}, {1:2}.keys():
+    for o in {1:2}, {1:2}.keys():
         print("{} in {}: {}".format(i, o, i in o))
         print("{} not in {}: {}".format(i, o, i not in o))
 

tests/basics/set_comprehension.py

+print({a for a in range(5)})

tests/basics/set_containment.py

+for i in 1, 2:
+    for o in {}, {1}, {2}:
+        print("{} in {}: {}".format(i, o, i in o))
+        print("{} not in {}: {}".format(i, o, i not in o))