[infra-tests] Stability script: strip backticks in markdown_adjust (#5135)

It doesn't work to escape backticks inside backticks, so instead
just remove them.

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See e.g. https://github.com/w3c/web-platform-tests/pull/5131#issuecomment-286174998 (the `opener.html` test)

View on GitHub: https://github.com/w3c/web-platform-tests/pull/5135

Received on Tuesday, 14 March 2017 09:01:19 UTC