(11) RFR (S) JDK-8197868: VS2017 (C2065) 'timezone': Undeclared Identifier in share/runtime/os.cpp

[Lois Foltan]

Please review this change to use the functional version of _get_timezone 
for VS2017.  The global variable timezone has been deprecated.

open webrev at http://cr.openjdk.java.net/~lfoltan/bug_jdk8197868/webrev/
bug link https://bugs.openjdk.java.net/browse/JDK-8197868
contributed-by: Kim Barrett & Lois Foltan

Testing: hs-tier(1-3), jdk-tier(1-3) complete

Thanks,
Lois