tracef should not emit a newline at the end
There should be some way to emit a string without a newline, and looks like `tracef` is the answer if it didn't emit the final newline. See https://github.com/aduros/wasm4/pull/611

In Forth it's idiomatic to emit lines like:
```
: foo ." 1+2=" 1 2 + . cr ;
```
With the current `tracef` behaviour it's inconvenient to implement that, since it would require buffering until a `cr` is performed.