Revert "test: disable recover4 test to fix ppc64 builds"

This reverts commit 1313e7982f44c24948e73c4795d9606265d36871.

Change-Id: I96cc58baf71156fdfbf8fd61332744bcc3ea52e5
Reviewed-on: https://go-review.googlesource.com/7670
Reviewed-by: Dave Cheney <dave@cheney.net>
diff --git a/test/recover4.go b/test/recover4.go
index 5f66a50..115d5a0 100644
--- a/test/recover4.go
+++ b/test/recover4.go
@@ -1,5 +1,4 @@
 // +build linux darwin
-// +build !ppc64,!ppc64le
 // run
 
 // Copyright 2015 The Go Authors.  All rights reserved.