RFR: JDK-8175795 configure should verify that system zlib contains needed functionality

[Magnus Ihse Bursie]

If we're using the system zlib instead of the bundled zlib, we should 
verify that it includes all relevant functions. We now rely on the 
inflateValidate() function, which was introduced in zlib 1.2.9 which is 
very recent. This patch adds a test to the system zlib to verify this 
and to fail fast in case it's too old.

Bug: https://bugs.openjdk.java.net/browse/JDK-8175795
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8175795-check-for-system-zlib-functionality/webrev.01

/Magnus