jdk repo clear of fallthrough lint warning; warning enabled in the build

[Joe Darcy]

Hello,

As part of the on-going lint warnings cleanup [1], the jdk repo of the 
JDK 9 dev forest is now clear of the javac switch statement 
"fallthrough" lint warning and the warning has been enabled in the 
build. [2]

(Progress has also been made on resolving the outstanding rawtype and 
unchecked warnings. There are only about 2,000 rawtype and unchecked 
warnings remaining, down from 4,000+ at the start of JDK 9 and 2,800 at 
the beginning of April. [3])

Cheers,

-Joe

[1] http://mail.openjdk.java.net/pipermail/jdk9-dev/2014-May/000781.html

[2] http://hg.openjdk.java.net/jdk9/dev/jdk/rev/b561412cd668

[3] http://mail.openjdk.java.net/pipermail/jdk9-dev/2014-April/000581.html