Revert "remove hand-coded methods for (U)Int128 on 32 bit systems (#53867)"

[topolarity]

We need to revert this for now. Resolves #58911

It seems that the back-end LLVM emits this libcall a lot less often than it used to, but it still happens sometimes and 32-bit Windows has no implementation of __divti3.

[oscardssmith]

Can we only revert the div/rem part of these changes? It looks like * works now.

[topolarity]

I think we can try that on master where we have some time to catch lingering regressions.

Since we were bitten by this over a year after the original PR merged, I'd prefer to do a full revert for 1.12 just to be safe.

[gbaraldi]

If llvm is just emitting libcalls here we should just revert the whole thing, it's not like the performance of this matters too much (128 bit on 32bit). The other option is to vendor a C implementation of this and link it in, but LLVM has issues with finding those sometimes

[oscardssmith]

IIUC LLVM is only emitting libcalls here because it is missing the lowering of these operations. The reason I had hoped to leave this to LLVM is I trust them to have better lowerings (e.g. using add with carry functions) which they appear to do for all backends except 32 bit windows.

That said, I don't object to a full revert (at least for the backports).

[topolarity]

Merged the full revert for now, but please free to re-land a modified version of the change for master @oscardssmith

[giordano]

I'm a bit late to the party, but perhaps comments in the code to explain why those methods are still needed would be useful. Commit message has some explanation (great!), but it requires a git blame to find the rationale.