test: set GOMAXPROCS=1 in fixedbugs/issue9110

With this fix,

GOMAXPROCS=8 ./all.bash

passes, at least on my machine.

Fixes #10216.

Change-Id: Ib5991950892a1399ec81aced0a52b435e6f83fdf
Reviewed-on: https://go-review.googlesource.com/9392Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

test/fixedbugs/issue9110.go

@@ -17,6 +17,7 @@ import (
 )
 
 func main() {
+	runtime.GOMAXPROCS(1)
 	debug.SetGCPercent(1000000) // only GC when we ask for GC
 
 	var stats, stats1, stats2 runtime.MemStats