bug#41321: 27.0.91; Emacs aborts due to invalid pseudovector objects

[Eli Zaretskii]

> Cc: pipcet@gmail.com, 41321@debbugs.gnu.org, monnier@iro.umontreal.ca
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Wed, 27 May 2020 09:58:11 -0700
> 
> we can then talk about what to do with emacs-27.

After thinking about this some, I think the only sensible thing to do
on emacs-27 is to return to 8-byte alignment test in GC for 32-bit
MinGW builds.  That is, replace max_align_t with just 8 in the
definition of LISP_ALIGNMENT in that case.