CL 156019 adds some debug output, including printing ssa.relation
as string. Update the map.

Change-Id: I0299d2008d199da10d86e5b47a50385b3a314c68
Reviewed-on: https://go-review.googlesource.com/c/156020
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>