Enhance find heap bound (#2579)

* Enhance find_heap_bound to not go smaller than min_step

Previously, it could accidentally get a step size smaller than the
min_step and just continue looping forever. Now the while loop has a new
termination condition to catch this case.

* Add context to find_heap_bound

This new option allows for checking additional heap sizes in increments
of the min_step above the found minimum heap size.