Unset LC_ALL and LC_COLLATE to stabilize regression test output

I set LC_COLLATE=C in ~/.profile, which appears to change the glob order.
LC_ALL would also affect that, so let's unset both.

sample_files/compare_all.sh

@@ -20,6 +20,7 @@ cargo build --release
 # Set language so we expand globs in a consistent order regardless of
 # locale (e.g. on GitHub actions).
 LANG=en_US.UTF-8
+unset LC_ALL LC_COLLATE
 
 echo "==> Check outputs"
 for before_f in sample_files/*before.*; do