On a Windows host, a test's file name reaches the device with backslashes #216

Describe the bug

Run from a Windows host, context.task.file.name is src\__tests__\normal\smoke.harness.ts instead of src/__tests__/normal/smoke.harness.ts, so the playground's smoke.harness.ts fails:

expected 'src\__tests__\normal\smoke.harness.ts' to be 'src/__tests__/normal/smoke.harness.ts' // Object.is equality

The Jest runner names a test file with path.relative(rootDir, testPath) (packages/jest/src/run.ts, execute-run.ts), which uses the host's separator. The same name goes to the device as the module Metro bundles, with the setup files, and to the file hooks and diagnostics.

I have a fix that converts those names to forward slashes. I can open a PR.

System Info

System:
  OS: Windows 11 10.0.26200
Binaries:
  Node: 26.8.1
Device: Android emulator, API 35, x86_64

React Native Harness Version

1.6.0 (main at bca0781)

Reproduction

https://github.com/callstackincubator/react-native-harness/blob/main/apps/playground/src/__tests__/normal/smoke.harness.ts

Steps to reproduce

1. On Windows, run react-native-harness --harnessRunner android src/__tests__/normal/smoke.harness.ts in apps/playground.
2. "Smoke test › should expose task context to tests" fails on the file name above.