[DebugInfo][RemoveDIs] Set new-dbg-info flag from Modules correctly (#82373)
It turns out there's a pathway for Functions to be inserted into modules
without having the "New" debug-info flag set correctly, which this patch
fixes. Sadly there isn't a Module::insert method to instrument out
there, everyone touches the list directly.
This fix exposes a path where such functions are produced in the
outliner in the wrong mode; requiring a fix there to correctly drop
RemoveDIs-mode debug-info. This is covered by
test/DebugInfo/AArch64/ir-outliner.ll