As described in an issue I filed for tcmalloc (https://github.com/google/tcmalloc/issues/229) if a sampled allocation happens to fall within the address space of the GuardedPageAllocator, then it will be validated upon deallocation, and there may be a crash if a memory bug is detected. (Note that, based on a reply on the issue, the likely issue is that the GuardedPageAllocator's address space overlaps with that of system alloc).

We should ensure that we won't crash on memory errors on our own patch, and also move the previously added line that sets the sampling rate to 0 to the top of the mongo initializer.