Addendum to bug #11764517 : don't create links for --mem directory, move the --vardir instead.

The new --secure-file-priv checks dereference any symlinks in the paths and compare the 
resolved paths.
Thus the 5.0 test suite must do as the 5.1 and up and avoid using symlinks.

mysql-test/mysql-test-run.pl

@@ -873,6 +873,10 @@ sub command_line_setup () {
 	last;
       }
     }
+
+    # point vardir to the mem location
+    $opt_vardir= $opt_mem;
+    undef $opt_mem;
   }
 
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