This version is very limited. It does not work when comments are present
anywhere in the initializer list, since we do not have a good way to
associate them to specific initalizer and move them around.
The fix-it is associated with the last ctor-order diagnostic and
reorders all initializers. This is better than providing fix for each
diagnostic generated, since user would have to apply them one-by-one.
This also fixes a bug that would trigger an assert() in dependent
classes, when initializer present in code might not be found in the
idealized list of initializers. That is related to PR7179.