Revert change accidentally included in runtime file updates. Closes #3998.

Author: brammool

src/testdir/Makefile

@@ -12,13 +12,13 @@ SCRIPTSOURCE = ../../runtime
 # Comment out this line to see the verbose output of tests.
 #
 # Catches SwapExists to avoid hanging at the ATTENTION prompt.
-#REDIR_TEST_TO_NULL = --cmd 'au SwapExists * let v:swapchoice = "e"' > /dev/null
+REDIR_TEST_TO_NULL = --cmd 'au SwapExists * let v:swapchoice = "e"' > /dev/null
 
 # Uncomment this line to use valgrind for memory leaks and extra warnings.
 #   The output goes into a file "valgrind.testN"
 #   Vim should be compiled with EXITFREE to avoid false warnings.
 #   This will make testing about 10 times as slow.
-#VALGRIND = valgrind --tool=memcheck --leak-check=yes --num-callers=25 --log-file=valgrind.$*
+# VALGRIND = valgrind --tool=memcheck --leak-check=yes --num-callers=25 --log-file=valgrind.$*
 
 default: nongui