Follow up Fix: Bug #18145121 - DEPRECATED PERL SYNTAX IN MTR

(cherry picked from commit 3eb933e0eb55f962404a04741767177e12a9885f)

Conflicts:
	mysql-test/mysql-test-run.pl

mysql-test/mysql-test-run.pl

@@ -490,7 +490,7 @@ sub main {
     }
   }
 
-  if ( not defined @$completed ) {
+  if ( not $completed ) {
     mtr_error("Test suite aborted");
   }