Bug: Switch statements cannot be one-lined

Choose one: is this a bug report or feature request?

Bug

### Input Code

```coffee
switch when true then yes
```

and

```coffee
switch a when true then yes
```

### Expected Behavior

The above should compile

### Current Behavior

It does not compile

### Possible Solution

### Context

### Environment

* CoffeeScript version:
* Node.js version:

Start by compiling the two switch examples from the issue and compare their failures with nearby switch syntax in the CoffeeScript compiler. Done means both one-line forms compile successfully; the issue does not identify a source file, test, or CoffeeScript and Node.js version.

Written by the indexing model from the issue text.