Add #pragma once to odbc_test_suite.h

To avoid redefinition error

Author: alinaliBQ

cpp/src/arrow/flight/sql/odbc/tests/odbc_test_suite.h

@@ -15,6 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
+#pragma once
+
 #include "arrow/testing/gtest_util.h"
 #include "arrow/util/io_util.h"
 #include "arrow/util/utf8.h"