LTS couple perf test and perf top fixes

["Rantala, Tommi T. (Nokia - FI/Espoo)" <tommi.t.rantala@xxxxxxxxx>]

Hi Greg, Sasha,

Can you pick this to 5.4:

commit dbd660e6b2884b864d2642d930a163d3bcebe4be
Author: Tommi Rantala <tommi.t.rantala@xxxxxxxxx>
Date:   Thu Apr 23 14:53:40 2020 +0300

    perf test session topology: Fix data path


And this to 5.4 and older LTS trees too:

commit 29b4f5f188571c112713c35cc87eefb46efee612
Author: Tommi Rantala <tommi.t.rantala@xxxxxxxxx>
Date:   Thu Mar 5 10:37:12 2020 +0200

    perf top: Fix stdio interface input handling with glibc 2.28+


Thanks!
-Tommi