test/bench/shootout: pidigits is much faster

Also fix a bug in the script (s/runonly/run/)

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6501051

test/bench/shootout/timing.log

@@ -1063,3 +1063,9 @@ pidigits 10000
 	gc pidigits	3.51u 0.00s 3.52r # -6%
 	gc_B pidigits	3.51u 0.00s 3.52r # -6%
 
+# Aug 28, 2012
+# After some assembler work in package big.
+pidigits 10000
+	gc pidigits	2.85u 0.02s 2.88r # -22%
+	gc_B pidigits	2.88u 0.01s 2.90r # -21%
+

test/bench/shootout/timing.sh

@@ -176,7 +176,7 @@ meteor() {
 
 pidigits() {
 	runonly echo 'pidigits 10000'
-	runonly 'gcc -O2 pidigits.c -lgmp' a.out 10000
+	run 'gcc -O2 pidigits.c -lgmp' a.out 10000
 	run 'gccgo -O2 pidigits.go' a.out -n 10000
 	run 'gc pidigits' $O.out -n 10000
 	run 'gc_B  pidigits' $O.out -n 10000