Meta: Strip query string from WPT test variants before importing them

The output of `WPT.sh list-tests` includes test variants, which vary
only by their query string. Since we don't care about this when
importing tests, ignore any query strings and ensure duplicates are
removed from the given test paths.

Meta/WPT.sh

@@ -221,17 +221,22 @@ import_wpt()
         INPUT_PATHS[i]="$item"
     done
 
-    TESTS=()
+    RAW_TESTS=()
     while IFS= read -r test_file; do
-        TESTS+=("$test_file")
+        RAW_TESTS+=("${test_file%%\?*}")
     done < <(
         "${ARG0}" list-tests "${INPUT_PATHS[@]}"
     )
-    if [ "${#TESTS[@]}" -eq 0 ]; then
+    if [ "${#RAW_TESTS[@]}" -eq 0 ]; then
         echo "No tests found for the given paths"
         exit 1
     fi
 
+    TESTS=()
+    while IFS= read -r test_file; do
+        TESTS+=("$test_file")
+    done < <(printf "%s\n" "${RAW_TESTS[@]}" | sort -u)
+
     pushd "${LADYBIRD_SOURCE_DIR}" > /dev/null
         ./Meta/ladybird.sh build headless-browser
         set +e