We never properly added support for this. This fixes vendoring when it
has npm or node specifiers. Vendoring occurs by adding a
`"nodeModulesDir": true` property to deno.json then it uses a local
node_modules directory. This can be opted out by setting
`"nodeModulesDir": false` or running with `--node-modules-dir=false`.
Closes #18090
Closes #17210
Closes #17619
Closes #16778
