Stored and restored original parent and span for each AST object (when calling Revert).
Stored and restored original parent and span for each AST object (when calling Revert).

IronLanguages/ironpython2,slozier/ironpython2,slozier/ironpython2,IronLanguages/ironpython2,IronLanguages/ironpython2,slozier/ironpython2,slozier/ironpython2,slozier/ironpython2,slozier/ironpython2,IronLanguages/ironpython2,IronLanguages/ironpython2,slozier/ironpython2,IronLanguages/ironpython2,IronLanguages/ironpython2