test: do not assume cwd in snapshot tests
In case the test is run from a different cwd, it should still pass.
Review requested:
- [ ] @nodejs/test_runner
CI: https://ci.nodejs.org/job/node-test-pull-request/59404/
CI: https://ci.nodejs.org/job/node-test-pull-request/59408/
Please do not resume CI when it has test failures related to the PR: process.chdir() is not supported in workers
CI: https://ci.nodejs.org/job/node-test-pull-request/59410/
CI: https://ci.nodejs.org/job/node-test-pull-request/59438/
CI: https://ci.nodejs.org/job/node-test-pull-request/59452/
CI: https://ci.nodejs.org/job/node-test-pull-request/59987/
Landed in 87598d4b63ef2c827a2bebdfa0f1540c35718519