cmd/dist: skip misc/cgo/test with internal linking on ppc64le

CL 22372 changed ppc64le to use normal cgo initialization on ppc64le.
Doing this uncovered a cmd/link error using internal linking.
Opened issue 15409 for the problem.  This CL disables the test.

Update #15409.

Change-Id: Ia1bb6b874c1b5a4df1a0436c8841c145142c30f7
Reviewed-on: https://go-review.googlesource.com/22379
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/dist/test.go

@@ -725,8 +725,10 @@ func (t *tester) cgoTest(dt *distTest) error {
 	cmd := t.addCmd(dt, "misc/cgo/test", "go", "test", t.tags(), "-ldflags", "-linkmode=auto")
 	cmd.Env = env
 
-	if t.gohostos != "dragonfly" {
+	if t.gohostos != "dragonfly" && t.gohostarch != "ppc64le" {
 		// linkmode=internal fails on dragonfly since errno is a TLS relocation.
+		// linkmode=internal fails on ppc64le because cmd/link doesn't
+		// handle the TOC correctly (issue 15409).
 		cmd := t.addCmd(dt, "misc/cgo/test", "go", "test", "-ldflags", "-linkmode=internal")
 		cmd.Env = env
 	}