test: create home for test-npm-install

[danbev]

This test currently fails if run as root:

npm ERR! makeDirectory homeless?
npm WARN install-dir No description
npm WARN install-dir No repository field.
npm WARN install-dir No license field.

npm ERR! path /root/node/test/.tmp.0/npm-sandbox/home
npm ERR! code ENOENT
npm ERR! errno -2
npm ERR! syscall stat
npm ERR! enoent ENOENT:
no such file or directory,
  stat '/root/node/test/.tmp.0/npm-sandbox/home'
npm ERR! enoent This is related to npm not being able to find a file.
npm ERR! enoent

assert.js:89
  throw new AssertionError(obj);
  ^

AssertionError [ERR_ASSERTION]: npm install got error code 254
    at handleExit (/root/node/test/parallel/test-npm-install.js:60:10)
    at /root/node/test/common/index.js:371:15
    at ChildProcess.exithandler (child_process.js:304:5)
    at ChildProcess.emit (events.js:203:13)
    at maybeClose (internal/child_process.js:1028:16)
    at Process.ChildProcess._handle.onexit
      (internal/child_process.js:283:5) {
       generatedMessage: false,
       code: 'ERR_ASSERTION',
       actual: 254,
       expected: 0,
       operator: 'strictEqual'
    }

The home directory will be created as expected by npm in the npmSandbox
when run as non-root, but when run as root this directory has to exist.

This commit creates the home directory to allow the test to pass also
when run as the root user.

Refs: https://github.com/npm/cli/blob/31718e72cb5a03cee7127fc36843e4b55c868d93/lib/utils/correct-mkdir.js#L82-L105

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/24209/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/24214/

[danbev]

Landed in cdd3833.