jdk-aarch32 builds on Travis CI

[Alex Kashchenko]

Hi,

Just FYI, I setup aarch32 builds for jdk8, 9 and 10 on public CI builders:

https://github.com/ojdkbuild/contrib_jdk8u-aarch32-ci
https://github.com/ojdkbuild/contrib_jdk9u-aarch32-ci
https://github.com/ojdkbuild/contrib_jdk10u-aarch32-ci

Builders take mercurial tag as an input, download corresponding sources 
from http://hg.openjdk.java.net/ , cross-compile them in ubuntu 14.04 
container using arm-linux-gnueabihf toolchain and then publish resulting 
binary to the github repo under the specified tag.

Published binaries (last tags) were smoke-tested running hotspot/sanity 
jtregs on an arm board.

-- 
-Alex