Add fall-through for bytesToHuman for very large values (just print the bytes)

We have seen an issue where an instance had a very large peak memory usage: `used_memory_peak:18446744073706301432`. The `bytesToHuman()` function can't stringify that properly (we get: `used_memory_peak_human:\x90\f\x83\xFB\x83\u007F`) so here's a version that resort to simply printing the bytes for too-large values.