QA: Fix TOC browser test

Since 65ca386d TOC is tied to the output of Parser::getTOCHTML
This means that the table of contents is not always present on
desktop, and now on mobile.

According to Parser::formatHeadings there must currently be at
least 4 headlines for the table of contents to work.

Change-Id: I27da46a67b203f678920beb5c0b18b9853634525
Merge "QA: Fix TOC browser test"