Upload Xcode derived data on failure in Darwin tests as an artifact.

If there are crashes in the test, the crash logs should be in there, and we can
try to debug those.

Author: bzbarsky-apple

.github/workflows/darwin.yaml

@@ -123,6 +123,12 @@ jobs:
               run: |
                   xcodebuild -target "MatterTvCastingBridge" -sdk iphoneos
               working-directory: examples/tv-casting-app/darwin/MatterTvCastingBridge
+            - name: Uploading Xcode derived data to debug the failure
+              uses: actions/upload-artifact@v4
+              if: ${{ failure() && !env.ACT }}
+                  name: darwin-framework-derived-data
+                  path: ~/Library/Developer/Xcode/DerivedData
+                  retention-days: 5
             - name: Uploading log files
               uses: actions/upload-artifact@v4
               if: ${{ failure() && !env.ACT }}