[llvm] [DebugInfo][RemoveDIs] Set new-dbg-info flag from Modules correctly (PR #82373)

[Jeremy Morse via llvm-commits]

jmorse wrote:

(Possibly to state the obvious: while the flag for what flavour of debug-info we're carrying has saved our necks in the past, the fact that it's masking coverage here is unhelpful, and cause for getting rid of it earlier).

https://github.com/llvm/llvm-project/pull/82373