Issue:
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Due to prefix match, database like 'k' was matching with 'ka' and events of 'ka' we getting displayed for 'show event' of 'k'.

Resolution:
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Scan for listing of events in a schema is made to be done on exact match of database (schema) name instead of just prefix.

mysql-test/r/events_bugs.result:
  modified expected file with the expected results.
mysql-test/t/events_bugs.test:
  added a test case to reproduce the scenario.
sql/event_db_repository.cc:
  Scan for schema name is made to be done on exact db name match.