Fix empty search page when search_as_you_type and dirhtml is used

[consideRatio]

The setupSearchAsYouType guard checked for a pathname ending in
/search.html, which the dirhtml builder's search/ URL never matches, so
the inline search removed the search page's #search-results container
(searchtools.js's render target) and recreated it empty inside the
search dialog, leaving the page blank. The Escape-key handler reached
resetSearchAsYouTypeResults through a second path with the same effect,
even under the html builder.

Force the search_as_you_type flag off on the dedicated search page from
the html-page-context hook instead, mirroring the pagename == 'search'
guard in layout.html. That disables every inline-search entry point
there through the existing flag guards, for every builder, and the
pathname check becomes dead code.