[DebugInfo][LSR] Avoid crashes on large integer inputs

SCEV-based salvaging in LSR translates SCEVs to DIExpressions. SCEVs may
contain very large integers but the translation does not support
integers greater than 64 bits. This patch adds checks to ensure
conversions of these large integers is not attempted. A regression test
is added to ensure no such translation is attempted.

Reviewed by: StephenTozer

PR: https://bugs.llvm.org/show_bug.cgi?id=51329

Differential Revision: https://reviews.llvm.org/D107438