Detect infinite recursion when evaluating function arguments

This fixes a regression introduced when consolidating recursion checks
in commit 1c8e0e55. When a function is called recursively during
evaluation of its arguments, the recursion check in
xsltApplySequenceConstructor is never reached. Readd recursion check
in exsltFuncFunctionFunction but use the template depth counter.

Fixes bug #777293:

https://bugzilla.gnome.org/show_bug.cgi?id=777293