Tests/LibWeb: Import my test rebaselining script

This is not a beautiful program, but it does allow you to regenerate
the baseline expectation for a given layout or text test with a single
command. :^)

Tests/LibWeb/rebaseline-libweb-test

@@ -0,0 +1,20 @@
+#!/bin/bash
+set +e
+
+t=$1
+if echo -n $t | grep ^file: ; then
+    t=$(echo -n $t | sed s@^file://@@)
+fi
+
+if echo -n $t | grep Layout ; then
+    mode_flag="-d"
+else
+    mode_flag="-T"
+fi
+
+input_dir=$(dirname $t)
+expected_dir=$(echo $input_dir | sed s/input/expected/)
+test_name=$(basename $t .html)
+cd $SERENITY_SOURCE_DIR/Build/lagom/Ladybird
+mkdir -p $expected_dir
+./headless-browser $mode_flag --layout-test-mode $input_dir/$test_name.html > $expected_dir/$test_name.txt