all: don't rebind variables in for loops

See https://tip.golang.org/wiki/LoopvarExperiment#does-this-mean-i-dont-have-to-write-x--x-in-my-loops-anymore

Updates https://github.com/tailscale/tailscale/issues/11058

Signed-off-by: Alex Chan <alexc@tailscale.com>

tstest/archtest/qemu_test.go

@@ -33,7 +33,6 @@ func TestInQemu(t *testing.T) {
 	}
 	inCI := cibuild.On()
 	for _, arch := range arches {
-		arch := arch
 		t.Run(arch.Goarch, func(t *testing.T) {
 			t.Parallel()
 			qemuUser := "qemu-" + arch.Qarch