This printed things like
```
in function 'f'
called on standard input
in function 'd'
called on standard input
in function 'b'
called on standard input
in function 'a'
called on standard input
```
As a first step, it removes the empty lines so it's now
```
in function 'f'
called on standard input
in function 'd'
called on standard input
in function 'b'
called on standard input
in function 'a'
called on standard input
```
See #5434.
Some more of the invocations are tested in this change:
- bad switches
- errors in configuration files
- regular command, configuration and init command ordering
- persistence of variables over command invocation.
- interactive and login switch use
- terminal exit code return
- version request
There are sure to be other invocations that should be tested, but
these give a fair number of them a go.
