Optimize (coerce x 'complex).

Transform it into appropriate calls to COMPLEX, coercing to proper
float types as necessary.

Closes lp#1309815.
Optimize (coerce x 'character) into (character x).
Remove a-random-comma-object-do-not-use from the core.

Run the test at cold-init, that way it's no longer needed.
Add changed file missing from commit [f6f734]