fix: Remove '/.node-spawn-wrap-' from lib/homedir.js export

This would cause lib/mungers/env.js to set SPAWN_WRAP_SHIM_ROOT
including '/.node-spawn-wrap-' when that variable should point to the
directory which should contain `.node-spawn-wrap-*`.

index.js

@@ -106,7 +106,7 @@ function setup(argv, env) {
   }
 
   const key = process.pid + '-' + crypto.randomBytes(6).toString('hex')
-  let workingDir = homedir + key
+  let workingDir = path.resolve(homedir, `.node-spawn-wrap-${key}`)
 
   const settings = JSON.stringify({
     module: __filename,

lib/homedir.js

@@ -2,7 +2,4 @@
 
 const os = require('os')
 
-const home = process.env.SPAWN_WRAP_SHIM_ROOT || os.homedir()
-const homedir = home + '/.node-spawn-wrap-'
-
-module.exports = homedir
+module.exports = process.env.SPAWN_WRAP_SHIM_ROOT || os.homedir()