Don't convert URLs inside `<pre>` and `<code>` tags when parsing string using `make_clickable()`.
Adds Unit Tests.

Props johnjamesjacoby, helen, nacin, adamsilverstein, sirbrillig. 
Fixes #23756.


Built from https://develop.svn.wordpress.org/trunk@26052


git-svn-id: http://core.svn.wordpress.org/trunk@25977 1a063a9b-81f0-0310-95a4-ce76da25c4cd