MXS-1724: Reimplement core dump detection

Reimplemented the core dump detection for 2.2.

maxscale-system-test/testconnections.cpp

@@ -766,6 +766,10 @@ int TestConnections::copy_maxscale_logs(double timestamp)
             maxscales->ssh_node_f(i, true, "cp %s %s/", maxscales->maxscale_cnf[i], log_dir_i);
             maxscales->ssh_node_f(i, true, "chmod a+r -R %s", log_dir_i);
         }
+
+        const char* command = "for i in `find /tmp/ -name 'core*'`; do test -e $i && exit 1; done";
+        int rc = maxscales->ssh_node_f(i, true, command);
+        assert(rc == 0, "Test should not generate core files");
     }
     return 0;
 }