for a prepared statement.

include/mysql.h:
  enumerator MYSQL_STATUS_STATEMENT_GET_RESULT was added
  into mysql_status enum.
include/mysql.h.pp:
  enumerator MYSQL_STATUS_STATEMENT_GET_RESULT was added
  into mysql_status enum.
libmysql/libmysql.c:
  Introduce a separate mysql state to distinguish the situation
  when we have a binary result set pending on the server from the
  situation when the result set is in text protocol.
  execute() modified: if mysql->status == MYSQL_STATUS_GET_RESULT
  before return then set it to value MYSQL_STATUS_STATEMENT_GET_RESULT.
  stmt_read_row_unbuffered() and mysql_stmt_store_result()
  were modified: added checking for mysql->status against
  MYSQL_STATUS_STATEMENT_GET_RESULT value instead of MYSQL_STATUS_GET_RESULT.
tests/mysql_client_test.c:
  added test_bug47485()