Add missing EXTRA DIST statement


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13116 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/helgrind/tests/Makefile.am b/helgrind/tests/Makefile.am
index fb0abe5..8e090f3 100644
--- a/helgrind/tests/Makefile.am
+++ b/helgrind/tests/Makefile.am
@@ -85,6 +85,7 @@
 		tc19_shadowmem.stderr.exp tc19_shadowmem.stderr.exp-mips32 \
 	tc20_verifywrap.vgtest tc20_verifywrap.stdout.exp \
 		tc20_verifywrap.stderr.exp tc20_verifywrap.stderr.exp-mips32 \
+		tc20_verifywrap.stderr.exp-s390x \
 	tc21_pthonce.vgtest tc21_pthonce.stdout.exp tc21_pthonce.stderr.exp \
 	tc22_exit_w_lock.vgtest tc22_exit_w_lock.stdout.exp \
 		tc22_exit_w_lock.stderr.exp \