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

[Michael Spencer via cfe-commits]

Bigcheese wrote:

I believe the Linux test failure was due to a test that should have failed. It had a case insensitive VFS for the headers, but not for the modulemap. When looking up `fw.framework/Modules/module.modulemap` it should fail because that path doesn't exist, and isn't made case insensitive by the VFS. I've fixed the test by making that path also part of the VFS and thus case-insensitive. I believe this still preserves the intent of the test because it still verifies that the module map path uses capital `FW`.

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