Remove special case in SRT generation with -split-sections
Previously we were using an empty ModuleSRTInfo for each Cmm group with -split-section. As far as I can see this has no benefits, and simplifying this makes another patch simpler (!1304 (merged)).
We also remove some outdated comments: we no longer generate one module-level SRT.
This is a RFC. @simonmar @bgamari could you comment on this? As far as I can see this has no benefits. I wonder if I'm missing something about how -split-sections
works.