testcrypt: handle int as a return type.

I accepted both 'int' and 'uint' as function argument types, but
hadn't previously noticed that only 'uint' is handled properly as a
return type. Now both are.

test/testcrypt.py

@@ -176,7 +176,7 @@ def make_retval(rettype, word, unpack_strings):
                       retwords[0])
     if rettype.startswith("val_"):
         return Value(rettype, word)
-    elif rettype == "uint":
+    elif rettype == "int" or rettype == "uint":
         return int(word, 0)
     elif rettype == "boolean":
         assert word == b"true" or word == b"false"