[Bug target/106097] undefined behaviors regarding integer shifts in loongarch_build_integer

[xry111 at mengyan1223 dot wang]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106097

--- Comment #4 from Xi Ruoyao <xry111 at mengyan1223 dot wang> ---
BTW I found this issue trying to triage PR106096, but I think it's not related
to this one.