In `ParallelScavengeHeap::check_gc_overhead_limit`:

```
log_debug(gc)("GC Overhead Limit: GC Time %f Free Space Young %f Old %f Counter %zu",
              (100 - _size_policy->mutator_time_percent()),
              percent_of(_young_gen->free_in_bytes(), _young_gen->capacity_in_bytes()),
              percent_of(_old_gen->free_in_bytes(), _young_gen->capacity_in_bytes()),
              _gc_overhead_counter);
```
should be `_old_gen` for the second arg of the second `percent_of`.

Git history shows that it's from JDK-8212084