[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:

Does preprocessing from AST files (ab75597ddac52f24e9cbd794cded195262ef670e) with decluse checking (f3f846162a5d6b5b84ed7d146a29dc175542c2c0) still work with this patch? I'm surprised that removing of module maps just because they only provided a textual header doesn't have any consequences in that area.

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