In multi_update::send_data(), the counter of matched rows was not correctly incremented, when during insertion of a new row to a temporay table it had to be converted from HEAP to MyISAM.

This fix changes the logic to increment the counter of matched rows in the following cases:
1. If the error returned from write_row() is zero.
2. If the error returned from write_row() is non-zero, is neither HA_ERR_FOUND_DUPP_KEY nor HA_ERR_FOUND_DUPP_UNIQUE, and a call to create_myisam_from_heap() succeeds. 


mysql-test/r/update.result:
  Added a test case for bug #22364 "Inconsistent "matched rows" when executing UPDATE"
mysql-test/t/update.test:
  Added a test case for bug #22364 "Inconsistent "matched rows" when executing UPDATE"
sql/sql_update.cc:
  In multi_update::send_data(), the counter of matched rows was not correctly incremented, when during insertion of a new row to a temporay table it had to be converted from HEAP to MyISAM.
  
  This fix changes the logic to increment the counter of matched rows in the following cases:
  1. If the error returned from write_row() is zero.
  2. If the error returned from write_row() is non-zero, is neither HA_ERR_FOUND_DUPP_KEY nor HA_ERR_FOUND_DUPP_UNIQUE, and a call to create_myisam_from_heap() succeeds.