Bug #48918 MTR uses an un-initialized value in comparison

mysqld->{proc} not defined for an embedded server
Check only if {proc} defined

mysql-test/mysql-test-run.pl

@@ -3893,7 +3893,7 @@ sub check_expected_crash_and_restart {
 
   foreach my $mysqld ( mysqlds() )
   {
-    next unless ( $mysqld->{proc} eq $proc );
+    next unless ( $mysqld->{proc} and $mysqld->{proc} eq $proc );
 
     # Check if crash expected by looking at the .expect file
     # in var/tmp