[clang] [clang][modules] Remove preloaded SLocEntries from PCM files (PR #66962)

[Jan Svoboda via cfe-commits]

jansvoboda11 wrote:

> > That said, isBeforeInTranslationUnit is slow already, and I don't think it's hot in clang, moreso in tools like clang-tidy whose performance is less-critical. So let's make it right, and then optimize it again if problems arise.
> 
> It may not be a hot function in Clang itself, but it is quite hot for some downstream Clang forks. While at Coverity, I had to avoid direct use of it because it was far too slow. Anything that speeds it up would be appreciated.

That's good to know, thanks! I think in it's current version, this patch shouldn't make that function slower, but I'll verify this after I get a green light on the semantic changes.

https://github.com/llvm/llvm-project/pull/66962