[gdb/testsuite] Fix host board local-remote-host-notty.exp timeouts

[gdb/testsuite] Fix host board local-remote-host-notty.exp timeouts

With test-case gdb.server/stop-reply-no-thread-multi.exp and host board
local-remote-host-notty.exp we occasionally run into a silent out, due to
getting:
...
(gdb) kill^M
(gdb) The program is not being run.^M
...
instead of the expected:
...
(gdb) kill^M
The program is not being run.^M
(gdb)
...

Likewise, we occasionally run into a nonsilent timeout:
...
(gdb) disconnect^M
(gdb) You can't do that when your target is `exec'^M
FAIL: gdb.server/stop-reply-no-thread.exp: to_disable=Tthread: t_nonstop=on: \
  disconnect (timeout)
...

Typically, this results in the test-case taking more than two minutes to run.

The problem can be reproduced using just:
...
$ ssh -l $USER 127.0.0.1 gdb -q -ex kill
...

Note that ssh by default uses -T which disables pseudo-tty allocation (as
opposed to -t which forces pseudo-tty allocation):
...
$ ssh -l $USER 127.0.0.1 -T tty
not a tty
$ ssh -l $USER 127.0.0.1 -t tty
/dev/pts/5
Connection to 127.0.0.1 closed.
...
and according to https://stackoverflow.com/a/63241102 the behaviour we're
seeing is specific to using '-T'.

The related host board local-remote-host.exp does use '-t', and the only
difference between the two boards mentioned is whether editing is on or off.

Fix this by:
- moving the content of local-remote-host-notty.exp into
  local-remote-host.exp
- consequently, extending the copyright years in local-remote-host.exp
- including local-remote-host.exp in local-remote-host-notty.exp
  (making local-remote-host-notty.exp use '-t')
- adding -iex "set editing off" to GDBFLAGS in local-remote-host-notty.exp

This results in the test-case taking just 6 seconds to run.

Tested on x86_64-linux.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29669