bug#34318: 26.1.90; Strange behavior of two line message with running shell

[Glenn Morris]

For me, with no shell involved, in emacs-26 but not master:

emacs -Q

Type in scratch:

(message "1\n2")

Press C-x C-e

-> two line message

Now type:

M-: (message "1\n2")

-> one line message "1\n2".

Now repeating C-x C-e on the original expression in scratch also
produces a one line message, forever more.