all: copyright headers outside of /src have inconsistent spacing

[martisch]

While /src was made consistent in 20111 to use single spaces in copyright headers many go file headers in e.g. /test and /misc remain inconsistent and could also be updated.

[odeke-em]

I'll send a CL for this.

[gopherbot]

CL https://golang.org/cl/21818 mentions this issue.

[gopherbot]

CL https://golang.org/cl/21819 mentions this issue.