upstream: Test did not compile due to missing symbols. Add source

sshbuf-misc.c to regress as it was done in ssh make file. from Moritz Buhl

OpenBSD-Regress-ID: 9e1c23476bb845f3cf3d15d9032da3ed0cb2fcf5
diff --git a/.skipped-commit-ids b/.skipped-commit-ids
index 177459e..11840a1 100644
--- a/.skipped-commit-ids
+++ b/.skipped-commit-ids
@@ -9,6 +9,7 @@
 db6375fc302e3bdf07d96430c63c991b2c2bd3ff	moduli update
 5ea3d63ab972691f43e9087ab5fd8376d48e898f	uuencode.c Makefile accident
 99dd10e72c04e93849981d43d64c946619efa474	include sshbuf-misc.c
+9e1c23476bb845f3cf3d15d9032da3ed0cb2fcf5	sshbuf-misc.c in regress
 
 Old upstream tree: