tests/base/struct1.py: Add test for repetition counters.

tests/basics/struct1.py

@@ -61,3 +61,8 @@ try:
     struct.pack(1, 2)
 except TypeError:
     print('TypeError')
+
+# Initially repitition counters were supported only for strings,
+# but later were implemented for all.
+print(struct.unpack("<3B2h", b"foo\x12\x34\xff\xff"))
+print(struct.pack("<3B", 1, 2, 3))