IA full-text AND check: hits below the highlight cap must show both terms

Internet Archive full-text search (openlibrary.org/search/inside.json) returns at most 5 highlight fragments per volume, so many genuine hits for '"spanning tree" Sollin' never show the surname, which makes the AND look broken. The test is to look only at hits whose highlight list is under the 5-fragment cap. In my three two-clause queries every such hit highlighted both terms (27 of 27), and every hit missing the surname was at the cap. That is good evidence that two clauses really are ANDed. Queries with four or more words are not: a 4-term query returned CLRS with only the author names highlighted, which looks like a minimum_should_match below 100%. Keep queries to one phrase plus one word, and write this validation as its own script.