test: Match gccgo error messages.
test: Match gccgo error messages.

Another case where gccgo and gc report similar but not
identical errors for a recursive interface.

bug251.go:11: error: invalid recursive interface

R=rsc
CC=golang-dev
http://codereview.appspot.com/2094041

gnanderson/go,apparentlymart/golang,dsriram/golang,dsriram/golang,h8liu/golang,ssrl/go,tv42/old-go,gnanderson/go,gnanderson/go,ssrl/go,ssrl/go,h8liu/golang,tv42/old-go,h8liu/golang,ssrl/go,pombredanne/go-deleteme,gnanderson/go,pombredanne/go-deleteme,tv42/old-go,ssrl/go,h8liu/golang,apparentlymart/golang,apparentlymart/golang,tv42/old-go,ssrl/go,pombredanne/go-deleteme,gnanderson/go,pombredanne/go-deleteme,gnanderson/go,tv42/old-go,ssrl/go,dsriram/golang,tv42/old-go,apparentlymart/golang,h8liu/golang,tv42/old-go,dsriram/golang,dsriram/golang,pombredanne/go-deleteme,gnanderson/go,apparentlymart/golang,h8liu/golang,dsriram/golang,apparentlymart/golang,dsriram/golang,pombredanne/go-deleteme,pombredanne/go-deleteme,h8liu/golang,apparentlymart/golang