[turbopack] Fix de-opt in getChunkRelativeUrl() (#96183)
Used Claude + this tool (https://github.com/vercel/next.js/pull/96158)
to look at Turbopack's runtime. With a large fixture with a lot of
imports, this part was bailing out:
```
{
"kind": "deopt",
"bailoutType": "deopt-eager",
"reason": "wrong map",
"functionName": "getChunkRelativeUrl",
"original": {
"source": "turbopack:///[turbopack]/browser/runtime/base/runtime-base.ts",
"line": 486,
"column": 11
},
"severity": "high"
}
```
After the fix, this went away.
---------
Co-authored-by: Luke Sandberg <lukesandberg@users.noreply.github.com>
