Remove explicit recursion in retainer profiling (fixes Trac #14758)
Retainer profiling contained a recursion that under
certain circumstances could lead to the stack overflow
in C code.
The idea of the improvement is to keep an explicit stack for the
object, more precise to reuse existing stack, but allow new type of
objects to be stored there.
There is no reliable reproducer that is not a big program
but in some cases foldr (+) 0 [1..10000000] can work.
Reviewers: bgamari, simonmar, erikd, osa1
Reviewed By: bgamari, osa1
Subscribers: osa1, rwbarton, carter
GHC Trac Issues: Trac #14758
Differential Revision: https://phabricator.haskell.org/D5351