Reference the correct issue and clarify failure

src/test/bench/shootout-k-nucleotide-pipes.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// ignore-android: FIXME(#10393)
+// ignore-android: FIXME(#10393) hangs without output
 // ignore-pretty very bad with line comments
 
 // multi tasking k-nucleotide

src/test/bench/shootout-k-nucleotide.rs

@@ -38,7 +38,7 @@
 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 // OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// ignore-android see #10393 #13206
+// ignore-android: FIXME(#10393) hangs without output
 
 #![feature(box_syntax, std_misc, collections)]
 

src/test/bench/shootout-reverse-complement.rs

@@ -38,7 +38,7 @@
 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 // OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// ignore-android see #10393 #13206
+// ignore-android: FIXME(#10393) hangs without output
 
 #![feature(libc, scoped)]