This introduces undesirable `Rails.logger` formatters (such as the syslog
formatter) onto a `Logger.new(STDERR)` for the console. The production
logger may be going elsewhere than standard io, so we can't presume to
reuse its formatter.

With syslog, this causes missing newlines in the console, so irb prompts
start at the end of the last log message.

We can work to expose the console formatter in another way to address
the original issue.

This reverts commit 026ce5dd, reversing
changes made to 6f0a69c5.