[clang] [Modules] Record whether VarDecl initializers contain side effects (PR #143739)

[Henrik G. Olsson via cfe-commits]

hnrklssn wrote:

> > The direction meets my expectation. I think you already have an existing test for swift. Maybe you can try to reduce a lit test from it.
> 
> Yeah, I've tried reducing a lit test, but my reduced case doesn't trigger the original assert because the initializer is already deserialized. I'm trying to figure out what the difference is.

Managed to create a reduced test case now that triggered the original assert, but doesn't with the current patch.

https://github.com/llvm/llvm-project/pull/143739