[dawn][generator] Sort the Python dependencies for the .d files

When running the Python-based generators, we gather the list of all
python files used and output it in the "deps" files for Ninja / CMake /
... This makes sure that if one of the script's files are changed, the
output are regenerated (as they might change).

This list wasn't determinitically ordered as internally it was likely
iterating over Python dictionaries. Sort the list before returning it to
make the order deterministic.

Fixed: 373485787
Change-Id: Ie590f1557d7bedee469920716d082d4ad1559cd5
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/210954
Auto-Submit: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: François Beaufort <fbeaufort@google.com>
Commit-Queue: Geoff Lang <geofflang@chromium.org>

generator/generator_lib.py

diff --git a/generator/generator_lib.py b/generator/generator_lib.py
index 0f58a52..f417190 100644
--- a/generator/generator_lib.py
+++ b/generator/generator_lib.py
@@ -262,7 +262,7 @@
 
         paths.add(path)
 
-    return paths
+    return sorted(paths)
 
 
 # Computes the string representing a cmake list of paths.