NMT reports will now show peak values for all categories. Peak values contain the highest value for committed memory in a given NMT category over the lifetime of the JVM process.

If the committed memory for an NMT category is currently at peak, NMT prints "at peak"; otherwise, it prints the peak value.

For example:
```
- Compiler (reserved=230KB, committed=230KB)
                            (malloc=34KB #64) (peak=49KB #71)
                            (arena=196KB #4) (peak=6126KB #16)
```

This shows Compiler arena memory peaked at a bit more than 6MB, whereas it now hovers around 200 KB.