Flaky test: GaugeTest.testTimer on Java 25

## Description

`GaugeTest.testTimer` fails on Java 25 with a timing assertion that's
too tight:

```text
Expecting actual:
  0.101583116
to be close to:
  0.012
```

at line 91. The test expects ~12ms but the timer measured ~101ms — likely
a scheduling delay on CI.

## Suggested fix

Use a more generous tolerance or assert `> 0` rather than closeness to
a specific wall-clock duration.