RFR(s): 8223313: Use handshakes for CountStackFrames.

[Robbin Ehn]

Hi all please review.

This change is part of parent issue:
Utilize handshakes instead of is_thread_fully_suspended
https://bugs.openjdk.java.net/browse/JDK-8223312

Issue:
https://bugs.openjdk.java.net/browse/JDK-8223313
Change-set:
http://cr.openjdk.java.net/~rehn/8223313/webrev/

The only test using this seems to be CountStackFramesAtExit.java which passes fine.

Thanks, Robbin