stack build --skip doesn't skip anything

> --skip ARG Skip given component, can be specified multiple times

### Steps to reproduce

```
mkdir stackholder
cd stackholder
stack new this
stack new that
rm {this,that}/stack.yaml
stack init
```

```
stack build --skip this
stack build --test --skip this
```

### Expected

Package `this` does not gets built and its tests are skipped.

### Actual

Package `this` is building and then its tests are running.

### Stack version

```
$ stack --version
Version 1.6.3, Git revision b27e629b8c4ce369e3b8273f04db193b060000db (5454 commits) x86_64 hpack-0.20.0
```

### Method of installation

* Official binary, downloaded from stackage.org or fpcomplete's package repository