MERGE16_FIXME: this should throw a 'pg_waldump‘

[chenjinbao1989]

src/test/singlenode_isolation2/sql/prevent_ao_wal.sql：52

MERGE16_FIXME: this should throw a 'pg_waldump: error: error in WAL record at 0/40247EF8: invalid record length at 0/40247F28: expected at least 24, got 0' ERROR, fix it later

[tuhaihe]

This issue has been fixed by #1820. If not, please re-open it.