Update prefalign in DebugInfo test (#3681)
Update for llvm-project commit llvm/llvm-project@193d7a6ace9f
("[MC,CodeGen] Update .prefalign for symbol-based preferred alignment
(#184032)", 2026-04-11).
Temporarily match both the old and new patterns, to ensure the test
also passes with outdated LLVM apt binaries on our CI.
Original commit:
https://github.com/KhronosGroup/SPIRV-LLVM-Translator/commit/f417c2db8409dfb
