bug#32588: 27.0.50; ‘default-directory’ not updated

["Andreas Röhler" <andreas.roehler@easy-emacs.de>]

‘default-directory’ not updated when dir was changed by a program

Recipe from emacs -Q:

M-x shell RET
cd
mkdir newdir
echo "cd \$HOME/newdir/" > tonewdir
chmod 700 tonewdir
. tonewdir
pwd

;;;
`pwd` prints correctly result of $HOME/newdir
while C-h v default-directory RET displays value of $HOME

Thanks,
Andreas

In GNU Emacs 27.0.50 (build 1, i686-pc-linux-gnu, GTK+ Version 3.14.5)
  of 2018-08-29
Repository revision: 190e85b8d286408a88bb611967e658639c48d6c5
Windowing system distributor 'The X.Org Foundation', version 11.0.11604000
System Description: Debian GNU/Linux 8 (jessie)

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Configured features:
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LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS GTK3 X11
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   value of $XMODIFIERS: @im=ibus
   locale-coding-system: utf-8-unix

Major mode: Shell

Minor modes in effect:
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   font-lock-mode: t
   blink-cursor-mode: t
   auto-composition-mode: t
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Load-path shadows:
None found.

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Memory information:
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