RFR: JDK-8223305: Compiler support for Switch Expressions

[Jan Lahoda]

Hi,

I'd like to ask for a review of changes to update javac to follow the 
current spec for switch expressions, in particular the break -> yield 
change:
http://cr.openjdk.java.net/~gbierman/jep354-jls-20190524.html

Webrev:
http://cr.openjdk.java.net/~jlahoda/8223303/webrev.00/

JBS:
https://bugs.openjdk.java.net/browse/JDK-8223305

Feedback is welcome!

Thanks,
    Jan