MDEV-7241: rpl.rpl_parallel2 fails sporadically in buildbot

There was a race, a small window between updating slave position and updating
Seconds_Behind_Master, during which the test case could see the wrong value.

Fix by waiting for the expected status to appear.
MDEV-7236: rpl.rpl_gtid_basic failed in buildbot with wait_condition timeout

Fix rare failures in test case rpl.rpl_gtid_basic:

 - Add another possible error code when a connection is killed.

 - Make sure that the IO thread has had time to complete its stop after START
   SLAVE UNTIL. Otherwise, START SLAVE might run before IO thread stop,
   leaving the test case with a stopped IO thread that eventually causes a
   wait timeout.
Fix wording in error log message, to be consistent with other messages ("IO thread" -> "I/O thread").
MDEV-7251: Test failure in rpl.rpl_parallel

There was a race. The test case was expecting the slave to start processing a
particular DELETE statement, then the test would stop the slave at this
point. But there was missing something to wait until the slave would actually
reach this point; thus depending on timing it was possible that the slave
would be stopped too early, causing .result file difference.

Fixed by adding an appropriate wait to the test case.
fix include/not_embedded.inc to be independent from the environment

in particular, not fail with --vertical_results
put at least some output-generating statement in the test

otherwise mysqltest complains "No queries executed but non-empty result file found!"
Merge branch '10.0' into bb-10.1-merge

Conflicts:
	.bzrignore
	VERSION
	cmake/plugin.cmake
	debian/dist/Debian/control
	debian/dist/Ubuntu/control
	mysql-test/r/join_outer.result
	mysql-test/r/join_outer_jcl6.result
	mysql-test/r/null.result
	mysql-test/r/old-mode.result
	mysql-test/r/union.result
	mysql-test/t/join_outer.test
	mysql-test/t/null.test
	mysql-test/t/old-mode.test
	mysql-test/t/union.test
	packaging/rpm-oel/mysql.spec.in
	scripts/mysql_config.sh
	sql/ha_ndbcluster.cc
	sql/ha_ndbcluster_binlog.cc
	sql/ha_ndbcluster_cond.cc
	sql/item_cmpfunc.h
	sql/lock.cc
	sql/sql_select.cc
	sql/sql_show.cc
	sql/sql_update.cc
	sql/sql_yacc.yy
	storage/innobase/buf/buf0flu.cc
	storage/innobase/fil/fil0fil.cc
	storage/innobase/include/srv0srv.h
	storage/innobase/lock/lock0lock.cc
	storage/tokudb/CMakeLists.txt
	storage/xtradb/buf/buf0flu.cc
	storage/xtradb/fil/fil0fil.cc
	storage/xtradb/include/srv0srv.h
	storage/xtradb/lock/lock0lock.cc
	support-files/mysql.spec.sh
disable mroonga temporarily: see MDEV-7246