[11] RFR: Request to backport April 2019 CPU changes into 11-dev

[Kevin Rushforth]

 Hi Johan,

I request approval to backport the changes from the just-released April 
2019 CPU to 11-dev.

1. Webrev for Apr 2019 CPU changes

http://cr.openjdk.java.net/~kcr/cpu-1904-sync/11-dev/webrev/

This is a straight backport (patch applies cleanly) of the one FX fix 
that went into the April CPU.

Thanks.

-- Kevin