cmd/dist: re-enable internal PIE test

For #17068

Change-Id: I4e3ab166f08100292b779b651a9acfbfb44a55cd
Reviewed-on: https://go-review.googlesource.com/29119
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/dist/test.go

@@ -423,8 +423,7 @@ func (t *tester) registerTests() {
 	}
 
 	// Test internal linking of PIE binaries where it is supported.
-	// TODO(crawshaw): enable when golang.org/issue/17068 is resolved
-	if false && t.goos == "linux" && t.goarch == "amd64" {
+	if t.goos == "linux" && t.goarch == "amd64" {
 		t.tests = append(t.tests, distTest{
 			name:    "pie_internal",
 			heading: "internal linking of -buildmode=pie",