fix: use resolve_symlinks for node.universal and node.server

[yukipastelcat]

This PR seems to fix following issue with symbolic links in the routes #8100
Minimal issue reproduction is available here: https://github.com/yukipastelcat/sveltekit-symlinks
Symbolic links in the reproduction repository will be created automatically during build, but my plugin is flaky, so you might need to run npm run build for the second time to reproduce the issue.

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pnpm test command does not exist, so I ran pnpm test:kit instead, some tests are failing, but they also do it in the main branch.

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[eltigerchino]

Thanks! The repro works well and I've tested the fix with it. Can you add a test for this? Maybe in one of the other test suite folders we could try to make it so the build fails? Otherwise, it looks good to me.

[dummdidumm]

symlink tests are close to impossible to write in a good way (for example there's one I believe which always fails on windows for me), so I'm ok with this not having a test