Use the default find if possible else fall back (#47522)

bin/internal/update_dart_sdk.sh

@@ -60,6 +60,13 @@ if [ ! -f "$ENGINE_STAMP" ] || [ "$ENGINE_VERSION" != `cat "$ENGINE_STAMP"` ]; t
       ;;
   esac
 
+  # Use the default find if possible.
+  if [ -e /usr/bin/find ]; then
+    FIND=/usr/bin/find
+  else
+    FIND=find
+  fi
+
   DART_SDK_BASE_URL="${FLUTTER_STORAGE_BASE_URL:-https://storage.googleapis.com}"
   DART_SDK_URL="$DART_SDK_BASE_URL/flutter_infra/flutter/$ENGINE_VERSION/$DART_ZIP_NAME"
 
@@ -93,8 +100,8 @@ if [ ! -f "$ENGINE_STAMP" ] || [ "$ENGINE_VERSION" != `cat "$ENGINE_STAMP"` ]; t
     exit 1
   }
   rm -f -- "$DART_SDK_ZIP"
-  find "$DART_SDK_PATH" -type d -exec chmod 755 {} \;
-  find "$DART_SDK_PATH" -type f $IS_USER_EXECUTABLE -exec chmod a+x,a+r {} \;
+  $FIND "$DART_SDK_PATH" -type d -exec chmod 755 {} \;
+  $FIND "$DART_SDK_PATH" -type f $IS_USER_EXECUTABLE -exec chmod a+x,a+r {} \;
   echo "$ENGINE_VERSION" > "$ENGINE_STAMP"
 
   # delete any temporary sdk path