xbps-src: shlib-provides for real -32bit subpackages broken

Since #45504 the nvidia package is broken, the nvidia package is special in that it builds -32bit packages as part of the x86_64 package and not the usual -32bit multilib method using i686.

What happens is that two packages will provide the same shlib, once the 64bit and once for 32bit. Resulting in the shlib-requires on that version breaking because it finds two the soname in two files.

=> nvidia-535.98_1: running pre-pkg hook: 04-generate-runtime-deps ...
   SONAME: libpthread.so.0 <-> glibc>=2.36_1
   SONAME: librt.so.1 <-> glibc>=2.36_1
   SONAME: libdl.so.2 <-> glibc>=2.36_1
   SONAME: libc.so.6 <-> glibc>=2.36_1
   SONAME: libm.so.6 <-> glibc>=2.36_1
   SONAME: libX11.so.6 <-> libX11>=1.2_1
   SONAME: libXext.so.6 <-> libXext>=1.0.5_1
   SONAME: libnvidia-ml.so.1 <-> nvidia-libs-32bit.soname
nvidia-libs-535.98_1
   SONAME: libgcc_s.so.1 <-> libgcc>=4.4.0_1
   SONAME: ld-linux-x86-64.so.2 <-> glibc>=2.36_1

I have a workaround for it, but the pattern matching is really dirty and I think there is probably a better solution.
https://gist.github.com/Duncaen/dbc27bead074d4629b1802c8b2fd910c

I'm also not sure if it it could happen that a soname appears in multiple subpackages for other reasons, might be worth to detect and that and error out instead.

Start with xbps-src and the 04-generate-runtime-deps pre-pkg hook, then compare the reported nvidia 64-bit and 32-bit SONAME handling with the workaround in the linked gist. Reproduce the duplicate SONAME case and define completion as correct shlib-provides and shlib-requires generation without breaking ordinary multilib packages.