[UBSan] Add noinline attribute to handlers that should never return.

FIx a problem reported by Jakub Jelinek: don't do early-exit from fatal
UBSan handlers: even if source location is disabled (i.e. acquired by
some other thread), we should continue the execution to make sure that:
a) some thread will print the error report before calling Die().
b) handler marked as noreturn will indeed not return.

Explicitly add "Die()" calls at the end of all fatal handlers to be
sure UBSan handlers don't introduce UB themselves.