Fix a number of problems in the test suite (no code bugs):

- mysql-test-run.pl --valgrind complains when all tests succeed.

 - perfschema.all_instances fail on non-linux, where ENABLE_TEMP_POOL
   is not set and therefore BITMAP mutex is not used.

 - MDEV-132: main.mysqldump fails because it depends on exact size of stdio
   buffers.

 - MDEV-99: rpl.rpl_cant_read_event_incident fails due to a race where the
   slave manages to connect while the test case is in the middle of setting up
   the master, causing the slave to replicate extra/wrong events.

 - MDEV-133: rpl.rpl_rotate_purge_deadlock fails because it issues a
   DEBUG_SYNC SIGNAL immediately followed by RESET; this means that sometimes
   the intended receipient has no time to see the signal before it is cleared
   by the RESET, causing wait to timeout.

mysql-test/suite/perfschema/t/all_instances.test

@@ -17,7 +17,10 @@ use performance_schema;
 # "where" filters out instances that can be conditionally compiled out
 #
 
-select name from mutex_instances where name not rlike '/(DEBUG_SYNC::mutex)$' group by name;
+select name from mutex_instances
+ where name not rlike '/(DEBUG_SYNC::mutex)$'
+   and name != 'wait/synch/mutex/mysys/BITMAP::mutex'
+ group by name;
 # CRYPTO_dynlock_value::lock exists only when building with OpenSSL (not YaSSL).
 select name from rwlock_instances
        where name not in ("wait/synch/rwlock/sql/CRYPTO_dynlock_value::lock")