Issue 4070: Cyclic markup detection unable to deal with non-linear code execution

Issue 4070: Cyclic markup detection unable to deal with non-linear code execution

This uses dynamic winding to keep the stack depth counts accurate even
in the presence of non-local exits like those used of
map-markup-commands.  It also changes the regtest
markup-cyclic-reference.ly since it seems too much trouble to trap both
cyclic references via a tortoise/hare algorithm as well as limiting the
maximum markup stack depth.