[Sparc] Don't emit __multi3 on 32-bit SPARC (#66362)

LLVM fails to build on 32-bit Solaris/SPARC: several programs fail to
link due to undefined references to `__multi3`. This reference is from
`lib/libLLVMScalarOpts.a(LoopStrengthReduce.cpp.o)`. However, This
function exists neither in the 32-bit `libgcc.a` nor in
`libclang_rt.builtins-sparc.a`. It's only defined in their 64-bit
counterparts.

The same issue affects several 32-bit targets, e.g. 32-bit PowerPC as
described in Issue #54460. The fix is the same: inhibit the libcall for
32-bit compilations. This patch does just that, regenerating the
affected testcases. It allows the build to complete.

Tested on `sparc-sun-solaris2.11`.