RFR(m): 8221734: Deoptimize with handshakes

[Robbin Ehn]

Hi all, please review.

Let's deopt with handshakes.
Removed VM op Deoptimize, instead we handshake.
Locks needs to be inflate since we are not in a safepoint.

Goes on top of:
https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2019-April/033491.html

Code:
http://cr.openjdk.java.net/~rehn/8221734/v1/webrev/index.html
Issue:
https://bugs.openjdk.java.net/browse/JDK-8221734

Passes t1-7 and multiple t1-5 runs.

A few startup benchmark see a small speedup.

Thanks, Robbin