[clang] [clang][modules] Lazily load by name lookups in module maps (PR #132853)

[Jan Svoboda via cfe-commits]

https://github.com/jansvoboda11 commented:

This now makes much more sense after the renames from the prep-commit. There are still some naming inconsistencies, though. For example `ModuleMap::loadModuleMapFile()` both **parses** and loads a module map file, but `ModuleMap::findOrLoadModule()` expects the module map file to be already parsed and only loads the module. I think there's value in making this distinction more explicit. Maybe we could say that loading a module/module map file consists of parsing and _materializing_? No we can consistently name functions that do one, the other, or both.

https://github.com/llvm/llvm-project/pull/132853