RFR [XS] : 8223685: used bundled zlib on AIX by default

[Baesken, Matthias]

Hello, please review this small  AIX - specific change .

Currently we use by default the bundled zlib  (= zlib coming with OpenJDK)   on Windows, on other platforms the system zlib.
However it is possible to switch to the bundled zlib  in the configure process .

We had some build issues on AIX  build systems with ancient system-zlibs ,  so I propose to use as default the bundled zlib on AIX too .
(would also mean that  we use a current 1.2.11  in the build on AIX which is not bad, on some AIX machines I've seen older zlibs)


Bug/webrev  :

https://bugs.openjdk.java.net/browse/JDK-8223685

http://cr.openjdk.java.net/~mbaesken/webrevs/8223685.0/webrev/

Thanks, Matthias