already set to RESERVED if the SQLITE_FCNTL_PERSIST_WAL setting is set and
a specific sequence of multiple journal mode changes occur.
Enhance pagerExclusiveLock() to deal with this.
[forum:/forumpost/8130545bc6|Forum post 8130545bc6]
FossilOrigin-Name: 2bb8d977392f635515aa4a36f6f763a2e4858f7adc1120519e2e74c04a9749b5
fix the persistent-wal mode feature of truncating the WAL on close so that
it always truncates the WAL to zero bytes.
FossilOrigin-Name: 09ccc4a1be7ba81890f10aac6623dd90dab4f990