Add new test file mysql_upgrade.test


BitKeeper/deleted/.del-abi_check.ic:
  Rename: include/abi_check.ic -> BitKeeper/deleted/.del-abi_check.ic
client/mysql_upgrade.c:
  Make mysql_upgrade search also in "client" dir so it can be run from a source dist.
mysql-test/mysql-test-run.pl:
  Make it possible for .test scripts to run "mysql_upgrade"
mysql-test/r/mysql_upgrade.result:
  New BitKeeper file ``mysql-test/r/mysql_upgrade.result''
mysql-test/t/mysql_upgrade.test:
  New BitKeeper file ``mysql-test/t/mysql_upgrade.test''