[clang] [ASTWriter] Do not allocate source location space for module maps used only for textual headers (PR #116374)

[Jan Svoboda via cfe-commits]

jansvoboda11 wrote:

Hi @ilya-biryukov, I wanted to apologize for the late reply (I was on a leave) and thank you for going through the test case and taking time to understand why it works. Sounds good!

https://github.com/llvm/llvm-project/pull/116374