Add integration test for garbled stacktraces

[javierhonduco]

https://github.com/javierhonduco/rbperf/blob/28e2f524b2f97703ca8e975fd23128361f34217f/src/rbperf.rs#L436

p ((struct RString)(*((rb_control_frame_t*) (ruby_current_vm_ptr->ractor->main_thread->ec->vm_stack + ruby_current_vm_ptr->ractor->main_thread->ec->vm_stack_size) - 2).iseq.body.location.label)).as.heap.ptr

set *(0x7fd016296c42+2) = 0xf
set {char [10]} 0x7fd016296c42 = 0xf