**Summary**
Fixes#4430.
`fakeroot` detection was added in #3924 (7a053e2ca0); it actually tests the exact opposite though.
**Test plan**
For testing this I added the line
```JavaScript
console.log("isFakeRoot", isFakeRoot());
```
I then tried the lines
```
./yarn global add
sudo ./yarn global add
fakeroot ./yarn global add
```
I also tried if `ROOT_USER` is now correct in [user-home-dir.js](0ef3bf1f03/src/util/user-home-dir.js) for these 3 commands.
```JavaScript
console.log("ROOT_USER", ROOT_USER);
```
Will also follow up with unit tests.
61f64ff3b4