bug#31325: 27.0.50; PROPOSAL: introduce a new function to recenter without redisplaying the frame

[John Shahid]

This BUG is a continuation of this help-gnu-emacs mailing list
thread [1]. As mentioned in the thread, I ran into a terminal flickering
issue in flycheck which turns out to be caused by `recenter'
redisplaying the frame when `recenter-redisplay' value is either `t' or
`tty'. I agree with the arguments in the thread to maintain the backward
compatible behavior. Instead, I'm proposing one of the following
alternatives:

1. introduce a new lisp function for recentering and discourage the use
of `recenter' from lisp (i.e. declaring it `interactive-only'), or
2. add a new `recenter-and-redisplay' and bound it to C-l

Also, Stefan's suggestion/possible solution:

3. adding an argument to `recenter' to control the redisplay behavior

[1]: http://lists.gnu.org/archive/html/help-gnu-emacs/2018-04/msg00326.html

In GNU Emacs 27.0.50 (build 1, x86_64-pc-linux-gnu)
 of 2018-04-16 built on 043fb36e1435
Repository revision: 6ec3ec7fbec2c04d5e9570b0470217cd97e5e7e6
System Description: Ubuntu 16.04.4 LTS

Configured using:
 'configure --without-x'

Configured features:
SOUND NOTIFY GNUTLS LIBXML2 ZLIB THREADS

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix