Make generate_system_module_map.sh more deterministic

Closes #19400.

PiperOrigin-RevId: 563109921
Change-Id: Ieca444d898d30a10dea9af6b4d8623b8fdb93a68

Author: BoleynSu

tools/cpp/generate_system_module_map.sh

@@ -18,7 +18,7 @@ set -eu
 echo 'module "crosstool" [system] {'
 
 for dir in $@; do
-  find -L "${dir}" -type f 2>/dev/null | sort | uniq | while read header; do
+  find -L "${dir}" -type f 2>/dev/null | LANG=C sort | uniq | while read header; do
     echo "  textual header \"${header}\""
   done
 done