github actions: Update interdiff for massive fuzzy diffing rework

For detailed information on what's different, see the new commits.

Here's a short summary written by Claude of what's changed in interdiff:

Fuzzy mode output is now organized into labeled sections instead of a
single stream of diffs with inline `INTERDIFF:` markers. The sections are:
delta differences (actual code changes between the patches), context
differences (surrounding code differences, e.g. from different kernel
versions), rejected hunks (unmatched hunks needing manual review), and
files only in one patch. Spurious noise from patches capturing different
amounts of context around the same change is automatically filtered out.
Several hunk matching bugs have also been fixed -- delta differences now
show the correct direction (patch1 -> patch2), and matching no longer
cross-contaminates when multiple similar code patterns exist in a file.

Author: kerneltoast

.github/workflows/validate-kernel-commits.yml

@@ -189,7 +189,7 @@ jobs:
       - name: Clone and build custom patchutils
         run: |
           # Security: Pin to specific commit to prevent supply chain attacks
-          EXPECTED_COMMIT="60a60b3909d0e29c0ff286f6a73de4168977b097"
+          EXPECTED_COMMIT="d90325ceaa8835b85db56ded37cf3407377078db"
 
           # Clone repository at the specific commit we want
           git clone https://github.com/kerneltoast/patchutils.git --depth=1 --revision="$EXPECTED_COMMIT"