bug#74381: High memory usage during guix pull (i686-linux, guile jit)

[Dariqq]

Yesterday I had a very weird situation,
I tried to pull f365d6c6365b823bae2ae06d53088088ee07fba7 which failed on 
i686 natively with the 'Failed to expand Heap by 8192 KiB' warning.

Rerun things on an x86_64 machine with -s i686-linux and building 
packages-base succededd with the guile process memory maxing out at 3.5 
GB  (+ another 500 MB for the guix process)

However when I then pulled on the i686 machine substituting the 
packages-base guix was then left in a halfbroken state claiming that 
rust-criterion-0.5 is unbound which led to an error for almost anything 
useful(i think determining librsvg-for-system).

I checked the guix (gnu packages crates-check) of that generation output 
and the scm file seemed file, so something must have gone horrible wrong 
when that one got (jit) - compiled.

Unfortunately I had to gc the evidence to continue.

I then rolled back, deleted and gced the broken generation and repulled 
(now 666f484fcfb03d801dc5c78a15501e01eb78567d) this time disabling 
guile-jit on the x86-64 machine as well, which drastically reduced 
memory consumption. After pulling that one on i686 aswell I had no 
further issues