UnifiedHighlighter ANALYSIS mode does not accurately highlight SpanNotQuery or MUST_NOT [LUCENE-9426]

If UnifiedHighlighter uses MemoryIndexOffsetStrategy, it does not treat SpanNotQuery correctly.
Since UnifiedHighlighter uses actual search in order to determine which locations to highlight, it should be consistent with search and only highlight locations in a document that really match the query. However, it does not for SpanNotQuery.

For the query spanNot(spanNear([content:100, content:dollars], 1, true), content:thousand, 0, 0)
it produces
A <b>100</b> fucking <b>dollars</b> wasn't enough to fix it. ... We need <b>100</b> thousand <b>dollars</b> to buy the house

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Migrated from [LUCENE-9426](https://issues.apache.org/jira/browse/LUCENE-9426) by Christoph Goller
Environment:
```
I tested with 8.5.1, but other versions are probably also affected.
```

Attachments: [TestUnifiedHighlighter.java](https://apache.github.io/lucene-jira-archive/attachments/LUCENE-9426/TestUnifiedHighlighter.java)

Start with the attached TestUnifiedHighlighter.java and reproduce the SpanNotQuery example using UnifiedHighlighter in ANALYSIS mode with MemoryIndexOffsetStrategy. Trace how the query determines highlighted locations, then verify the result against actual search matching. Done means SpanNotQuery and MUST_NOT highlights include only locations that truly match the query.

Written by the indexing model from the issue text.