Minimal repro of an issue found in vi.useFakeTimers

When using vi.useFakeTimers to fake setTimeout, 1.2.x throws process is not defined errors. I think this was introduced in #4441 which standardized to using a isChildProcess helper function instead of various checks against globalThis.__vitest_worker__.isChildProcess.

To repro

npm install
npm run test

Expected: the test passes

Actual: ReferenceError: process is not defined

Note that the first commit in this repo abe06c7 passes when using 1.1.x