Fix random failures in test 'wait_timeout' that depend on exact timing.

1. Force a reconnect initially if necessary, as otherwise slow startup
might have caused a connection timeout before the test can even start.

2. Explicitly disconnect the first connection to remove confusion about
which connection aborts from timeout, causing test failure.


mysql-test/r/wait_timeout.result:
  Fix two races in test.
mysql-test/t/wait_timeout.test:
  Fix two races in test.