input: fix(zip-it-and-ship-it): create missing symlinks when archiveFormat=none

This change updates zisi's node bundler to create missing symlinks in
when `archiveFormat: 'none'` (the code path used by `netlify dev`).

Currently, in projects where two or more symlinks resolve to the same
target, we only ever create one symlink. In practice, how this usually
presents a problem is when a package manager dedupes a dependency by
symlinking it into two different packages; users end up getting a
runtime error when their code hits the code path that tries to resolve
the missing symlink.

For example, given this scenario (which I took from a project that
exhibits this issue):

```
{
  targetPath: '../../../@netlify[email protected]/node_modules/@netlify/sdk--extension-api-client',
  absoluteDestPath: '/home/ndhoule/dev/src/github.com/netlify/integration-csp/.netlify/functions-serve/trpc/node_modules/.pnpm/@netlify[email protected]_@[email protected]/node_modules/@netlify/sdk--extension-api-client'
}
{
  targetPath: '../../../@netlify[email protected]/node_modules/@netlify/sdk--extension-api-client',
  absoluteDestPath: '/home/ndhoule/dev/src/github.com/netlify/integration-csp/.netlify/functions-serve/trpc/node_modules/.pnpm/@netlify[email protected]_@[email protected]_@[email protected]_@[email protected]._vp3jgimrs3u5kdeagmtefgn5zi/node_modules/@netlify/sdk--extension-api-client'
}
```

...only the second symlink is created. This is because as we walk
through the list of files to output to the build directory, we only
track a single symlink destination per target. Many symlinks can point
at the same target, though, so we need to track multiple symlink
destinations per target.

I tested this out in my problem projects and it solved the problem. I
took a stab at adding a test for this, but got a little lost in the test
setup, which seems to have the `.zip` code path in mind rather than the
`'none'` path. Happy to write some tests if someone can point me at a
test setup.

Author: ndhoule

packages/zip-it-and-ship-it/src/runtimes/node/utils/zip.ts

@@ -129,7 +129,7 @@ const createDirectory = async function ({
     addBootstrapFile(srcFiles, aliases)
   }
 
-  const symlinks = new Map<string, string>()
+  const symlinks = new Map<string, Set<string>>()
 
   // Copying source files.
   await pMap(
@@ -156,7 +156,8 @@ const createDirectory = async function ({
       if (stat.isSymbolicLink()) {
         const targetPath = await readLink(srcFile)
 
-        symlinks.set(targetPath, absoluteDestPath)
+        // Two symlinks may point at the same target path, so keep a list of symlinks to create.
+        symlinks.set(targetPath, (symlinks.get(targetPath) ?? new Set()).add(absoluteDestPath))
 
         return
       }
@@ -168,9 +169,11 @@ const createDirectory = async function ({
 
   await pMap(
     [...symlinks.entries()],
-    async ([target, path]) => {
-      await mkdir(dirname(path), { recursive: true })
-      await symlink(target, path)
+    async ([target, paths]) => {
+      for (const path of paths) {
+        await mkdir(dirname(path), { recursive: true })
+        await symlink(target, path)
+      }
     },
     {
       concurrency: COPY_FILE_CONCURRENCY,