test/chan: fix broken link to Squinting at Power Series

Change-Id: Idee94a1d93555d53442098dd7479982e3f5afbba
Reviewed-on: https://go-review.googlesource.com/c/161339Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

test/chan/powser1.go

@@ -11,7 +11,7 @@
 // coefficients.  A denominator of zero signifies the end.
 // Original code in Newsqueak by Doug McIlroy.
 // See Squinting at Power Series by Doug McIlroy,
-//   http://www.cs.bell-labs.com/who/rsc/thread/squint.pdf
+//   https://swtch.com/~rsc/thread/squint.pdf
 
 package main
 

test/chan/powser2.go

@@ -15,7 +15,7 @@
 // coefficients.  A denominator of zero signifies the end.
 // Original code in Newsqueak by Doug McIlroy.
 // See Squinting at Power Series by Doug McIlroy,
-//   http://www.cs.bell-labs.com/who/rsc/thread/squint.pdf
+//   https://swtch.com/~rsc/thread/squint.pdf
 
 package main