Don't use SearchResult->initText.

SearchResult->initText isn't compatible with wgSearchTypeAlternatives.
It uses the default SearchEngine.  This isn't worth fixing in core
because wgSearchTypeAlternatives is a bit of a hack and CirrusSearch
only uses initText as a work around for an Elasticsearch bug that is
being solved.

Bug: 54644
Change-Id: Iebd411098e3d8e99b02e10ec08052932779cc9db
Merge "Don't use SearchResult->initText."