Blitzy: test_runner: bind built-in coverage exclusions to cwd-relative paths (fixes nodejs/node#58654) - #1

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea, Mozilla-Actions/sccache-action@7d986dd989559c6ecdb630a3fd2557667be217ad. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/