AssertionError in BooleanQuery.hashCode() [LUCENE-10431]

Hello devs,

the constructor of BooleanQuery can under some circumstances trigger a hash code computation before "clauseSets" is fully filled. Since BooleanClause is using its query field for the hash code too, it can happen that the "wrong" hash code is stored, since adding the clause to the set triggers its hashCode().

If assertions are enabled the check in BooleanQuery, which recomputes the hash code, will notice it and throw an error.

exception:

```java
java.lang.AssertionError
    at org.apache.lucene.search.BooleanQuery.hashCode(BooleanQuery.java:614)
    at java.base/java.util.Objects.hashCode(Objects.java:103)
    at java.base/java.util.HashMap$Node.hashCode(HashMap.java:298)
    at java.base/java.util.AbstractMap.hashCode(AbstractMap.java:527)
    at org.apache.lucene.search.Multiset.hashCode(Multiset.java:119)
    at java.base/java.util.EnumMap.entryHashCode(EnumMap.java:717)
    at java.base/java.util.EnumMap.hashCode(EnumMap.java:709)
    at java.base/java.util.Arrays.hashCode(Arrays.java:4498)
    at java.base/java.util.Objects.hash(Objects.java:133)
    at org.apache.lucene.search.BooleanQuery.computeHashCode(BooleanQuery.java:597)
    at org.apache.lucene.search.BooleanQuery.hashCode(BooleanQuery.java:611)
    at java.base/java.util.HashMap.hash(HashMap.java:340)
    at java.base/java.util.HashMap.put(HashMap.java:612)
    at org.apache.lucene.search.Multiset.add(Multiset.java:82)
    at org.apache.lucene.search.BooleanQuery.(BooleanQuery.java:154)
    at org.apache.lucene.search.BooleanQuery.(BooleanQuery.java:42)
    at org.apache.lucene.search.BooleanQuery$Builder.build(BooleanQuery.java:133)
```

I noticed this while trying to upgrade the NetBeans maven indexer modules from lucene 5.x to 8.x https://github.com/apache/netbeans/pull/3558

---
Migrated from [LUCENE-10431](https://issues.apache.org/jira/browse/LUCENE-10431) by Michael Bien (@mbien), updated Mar 04 2022
Pull requests: https://github.com/apache/lucene/pull/722, https://github.com/apache/lucene/pull/727

Start in org.apache.lucene.search.BooleanQuery, especially BooleanQuery.java around hashCode(), computeHashCode(), and the constructors, then inspect Multiset.java where the stack trace shows the hash is triggered. Compare the issue with pull requests 722 and 727; done means the reported assertion no longer occurs when BooleanQuery clauses are built and hashed.

Written by the indexing model from the issue text.