Memory leak hunting - Rhino script woes leading to stale metadata not being garbage collected

[Cantor, Scott]

Not a surprising outcome, but I wanted to note that the more common case
of attribute resolution scripts also creates a SimpleScriptContext that
contains a direct reference to a SAMLProfileRequestContext, which is the
same object being referenced in the filter case, so the attribute resolver
should also be creating this problem if it exists.

That seems to point to an environmental issue since it's not being
observed more widely.

-- Scott