#1767 Json: tojson applied to a not empty directory raises error "too many arguments"

[jfaucher]

Method parseRexxString
The instruction 'use strict arg rexxObject' is too strict.
The method accepts an optional second argument: if arg(2, 'e')

To reproduce:
say .json~new~toJson(.directory~of( ("key1", "value1"), ("key2", "value2")))

Fix and tests in attached patches.

[Erich]

Fixed code and updated test with revision [r12255]
Thanks for the patch, Jean-Louis!