Fix build test json report

[krichprollsch]

We are tracking the zig build test resultd with the --json output (https://perf.lightpanda.io/benchmark/browser)
But it doesn't work anymore.

zig build test -- --json
[...]
[
  {
    "name": "browser",
    "bench": {
      "duration": 8757177,
      "alloc_nb": 1,
      "realloc_nb": 0,
      "alloc_size": 2248
    }
  },
  {
    "name": "libdom",
    "bench": {
      "duration": 8757177,
      "alloc_nb": 0,
      "realloc_nb": 0,
      "alloc_size": 0
    }
  },
  {
    "name": "v8",
    "bench": {
      "duration": 8757177,
      "alloc_nb": 0,
      "realloc_nb": 0,
      "alloc_size": 0
    }
  },
  {
    "name": "main",
    "bench": {
      "duration": 8757177,
      "alloc_nb": 0,
      "realloc_nb": 0,
      "alloc_size": 0
    }
  }
]

[karlseguin]

You mean the allocations?

[karlseguin]

oh, nothing works.

[krichprollsch]

The weird thing is: I do have duration in my example, but on ci, we don't have anything 🤔

https://lpd-perf.s3.eu-west-3.amazonaws.com/bench/browser/history.json

It's not clear to me where the issue comes from.