Add embedder test comparing with the last patch.

When there is a wrong keyword like '??ze' in the dictionary
of the trailer, PDFium can't recognize it and aborts further
parsing. After this change, PDFium continues even it can't
get the right size at this moment. It will rebuild the cross
reference table later since the size of the table is missing.

BUG=459580
R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1055323003
6 files changed