Add a <medium> to simple_xfa.{in,pdf}.

Otherwise the PDF has no page dimensions and cannot be rendered.

Change-Id: I3a48e28b175aab2803b9697ca94a05fd45f6b8cf
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/68472
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
diff --git a/testing/resources/simple_xfa.in b/testing/resources/simple_xfa.in
index b20c746..d3c2d00 100644
--- a/testing/resources/simple_xfa.in
+++ b/testing/resources/simple_xfa.in
@@ -12,6 +12,7 @@
     <pageSet>
       <pageArea name="Page1" id="Page1">
         <contentArea x="0.25in" y="0.25in" w="8in" h="10.5in" />
+        <medium long="11in" short="8.5in" stock="letter"/>
       </pageArea>
     </pageSet>
     <field name="TextField1" y="31.75mm" x="44.45mm" w="114.291mm" h="12.7mm">