Meta: Remove unnecessary -i

Using `xargs -i <cmd> {}` is just doing the default behavior of xargs,
but with extra steps that also don't work on macOS.

Meta/check-ak-test-files.sh

@@ -14,7 +14,7 @@ while IFS= read -r FILENAME; do
         MISSING_FILES=y
     fi
 done < <(
-    git ls-files 'Tests/AK/Test*.cpp' | xargs -i basename {}
+    git ls-files 'Tests/AK/Test*.cpp' | xargs basename
 )
 
 if [ "n" != "${MISSING_FILES}" ] ; then