x/arch/ppc64/ppc64asm: skip ObjdumpPowerManual on some hosts

The TestObjdumpPowerManualTest compares the go disassembler
output against the host objdump, but if the test is not being
run on a ppc64 or ppc64le, the host objdump won't be correct
for the test, so skip it in that case.

Change-Id: I34ba6f3efa5bde1248a1e2eaeb110a8c8dc95ea9
Reviewed-on: https://go-review.googlesource.com/32510
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/ppc64/ppc64asm/objdumpext_test.go b/ppc64/ppc64asm/objdumpext_test.go
index 55cff31..7483543 100644
--- a/ppc64/ppc64asm/objdumpext_test.go
+++ b/ppc64/ppc64asm/objdumpext_test.go
@@ -14,6 +14,7 @@
 	"io"
 	"log"
 	"os"
+	"runtime"
 	"strconv"
 	"strings"
 	"testing"
@@ -25,6 +26,9 @@
 	if testing.Short() {
 		t.Skip("skipping objdump test in short mode")
 	}
+	if runtime.GOARCH != "ppc64le" && runtime.GOARCH != "ppc64" {
+		t.Skip("skipping; test requires host tool objdump for ppc64 or ppc64le")
+	}
 	if _, err := os.Stat(objdumpPath); err != nil {
 		t.Skip(err)
 	}