ogle/program/server: clarify ordering of evaluation when ptraceRun
wraps a closure that 'returns' more than just an error.

I don't think this changes the actual behavior with the gc compiler,
but a different compiler might not optimize the "return foo" part
as a no-op, in:
func f() (foo int, err error) {
        etc
        return foo, <-s.ec
}
and then it's possibly racy whether foo is evaluated before or after
the channel receive.

LGTM=r
R=r
https://golang.org/cl/89750043
1 file changed