test/bench: move to test/bench/shootout

R=golang-dev, r, gri, bradfitz
CC=golang-dev
https://golang.org/cl/5487067
diff --git a/src/run.bash b/src/run.bash
index 64514bc..5e27fc2 100755
--- a/src/run.bash
+++ b/src/run.bash
@@ -101,7 +101,7 @@
 done
 
 [ "$GOARCH" == arm ] ||
-(xcd ../test/bench
+(xcd ../test/bench/shootout
 ./timing.sh -test
 ) || exit $?