`test-os-process-priority` failing on my Windows machine

Version: master
Platform: Windows
Subsystem: os

When I run the test suite I get the following failure:

=== release test-os-process-priority ===
Path: parallel/test-os-process-priority
assert.js:84
  throw new AssertionError(obj);
  ^

AssertionError [ERR_ASSERTION]: Expected inputs to be strictly equal:

-14 !== -20

    at checkPriority (E:\GitHub\node\test\parallel\test-os-process-priority.js:120:12)
    at Object.<anonymous> (E:\GitHub\node\test\parallel\test-os-process-priority.js:97:3)
    at Module._compile (internal/modules/cjs/loader.js:689:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
    at Module.load (internal/modules/cjs/loader.js:599:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
    at Function.Module._load (internal/modules/cjs/loader.js:530:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:742:12)
    at startup (internal/bootstrap/node.js:270:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:801:3)
Command: E:\GitHub\node\Release\node.exe E:\GitHub\node\test\parallel\test-os-process-priority.js

I verified manually that setting the highest priority on my machine ends up setting high priority without any errors:

> const os = require('os')
undefined
> os.getPriority(0)
0
> os.setPriority(0, os.constants.priority.PRIORITY_HIGHEST)
undefined
> os.getPriority(0)
-14
> os.constants.priority.PRIORITY_HIGHEST
-20

It seems like although I'm asking for the highest priority Windows is pushing me down a level.