Incorrect values produced compared to pprof command

We're seeing this for Go memory profiles, but not for jemalloc heap profiles converted into pprof format.

Here's an example:

```
$ pprof heap.pprof
File: rrdns-external-auth
Build ID: b4d05855f9b8b7cb25be5eb6fb8eb56b21bf5a22
Type: inuse_space
Time: May 15, 2025 at 11:15pm (UTC)
Entering interactive mode (type "help" for commands, "o" for options)
(pprof) top1
Showing nodes accounting for 755.15MB, 21.54% of 3506.41MB total
Dropped 318 nodes (cum <= 17.53MB)
Showing top 1 nodes out of 157
flat flat% sum% cum cum%
755.15MB 21.54% 21.54% 755.15MB 21.54% io.ReadAll
```

Compare to what `pprofutils` produces for just one stack leading to `ReadAll`:

```
$ pprofutils folded -headers heap.pprof - | grep io.ReadAll | head -n1
go.cfdata.org/dns/rrdns/rrdns/util.Reloader.func1;...;io.ReadAll 2937092155 1503791184027 0 0
```

All of the numbers in the output are already too bigto fit into 3506.41MB of total allocation.