Fix langauge converter parser test with self-close tags

This fixes an issue in f21f3942 where if there was an html
element with an alt or title attribute containing an <
entity, an ascii EOT control character (0x04) may become
inserted into the text if language converter was enabled.

Due to a really old bug in language converter, self-closed tags
got turned into non-self closed tags. However due a different
bug which was fixed in f21f3942 this code path was rarely taken
so nobody noticed until now.

Follow-up Idbc45cac12

Bug: T180552
Change-Id: I077d30c50fcb419837fef937d27caca307153d2d