Revert "startup: use `path.resolve` instead of `path.join(cwd, ...)`"

Revert "startup: use `path.resolve` instead of `path.join(cwd, ...)`"

This reverts commit b0c15412270f32e00c268c578f07a1ed032323f5.

Reverted commit introduced a regression causing `process.argv[0]` to be
invalid in node processes spawned from `PATH` (without explicit path to
executable file - for example when using global node installation).

Instead of finding a correct path to the executable, `process.cwd()`
would be prepended to `process.argv[0]`.