build: add few tests with GOMAXPROCS=32 to run.bash

Some class of bugs (data races, runtime bugs) can be found
only with real parallelism.
Note that GOMAXPROCS=32 is somewhat different from go test -cpu=32,
this intentionally uses GOMAXPROCS to stress program bootstrap,
testing code, garbage collections, etc.
Package selection is mostly random.

R=golang-dev, dave, r
CC=golang-dev
https://golang.org/cl/6346070

src/run.bash

@@ -39,6 +39,11 @@ echo
 
 echo '# sync -cpu=10'
 go test sync -short -timeout=120s -cpu=10
+echo
+
+echo '# GOMAXPROCS=32 go test runtime net/http crypto/tls encoding/base64'
+GOMAXPROCS=32 go test runtime net/http crypto/tls encoding/base64
+echo
 
 xcd() {
 	echo