test/run: use go tool compile + link instead of go run when possible

This cuts 6 seconds off all.bash with the new go command.
Not a ton, but also an easy 6 seconds to grab.

The -tags=use_go_run in the misc/cgo tests is just some
go command flag that will make run.go use go run,
but without making everything look stale.
(Those tests have relative imports,
so go tool compile+link is not enough.)

Change-Id: I43bf4bb661d3adde2b2d4aad5e8f64b97bc69ba9
Reviewed-on: https://go-review.googlesource.com/73994
Reviewed-by: Ian Lance Taylor <iant@golang.org>

misc/cgo/life/main.go

@@ -1,4 +1,4 @@
-// cmpout
+// cmpout -tags=use_go_run
 
 // Copyright 2010 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
@@ -11,9 +11,10 @@
 package main
 
 import (
-	"."
 	"flag"
 	"fmt"
+
+	"."
 )
 
 const MAXDIM = 100