[llvm] [DataFlowSanitizer] Properly add ext attributes on arguments as needed. (PR #225443)

[Jonas Paulsson via llvm-commits]

JonPsson1 wrote:

Just doing one little change before committing: use maybeAddParamAttribute() instead of checking for None in getCustomFunctionType().

https://github.com/llvm/llvm-project/pull/225443