Pipeline stage not shown in queue while waiting for resource

I recently switched from

```
lock('LOCK') {
stage('Integration test') {
# Doing stuff
}
}
```

to

```
stage('Integration test') {
options {
lock('LOCK')
}
# Doing stuff
}
```

The reason was to avoid having an executor slot occupied while waiting for the resource.
I expected the build to instead be shown in the build queue as non Pipeline builds are while waiting for a resource. But this is not the case, instead the build is invisible until the resource is acquired.

Compare the two Declarative Pipeline examples in the issue and investigate how the pipeline stage behaves while its lockable resource is unavailable. The work is done when the waiting build is visible in the Jenkins build queue, as expected for non-Pipeline builds, without occupying an executor.

Written by the indexing model from the issue text.