test: don't require specific GOARCH values.
test: don't require specific GOARCH values.

This lets the test work for gccgo on other architectures.

R=r, rsc1
CC=golang-dev
http://codereview.appspot.com/4326044

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang