[clang] load umbrella dir headers in sorted order (#156108)

Clang modules sort the umbrella dir headers by name before adding to the
module's includes to ensure deterministic output across different file
systems.
This is insufficient however, as the header search table is also
serialized.
This includes all the loaded headers by file reference, which are
allocated
incrementally. To ensure stable output we have to also create the file
references in sorted order.

0 files changed, 0 insertions, 0 deletions