[11u] RFR: 8223490: Optimize search algorithm for determining default time zone

[Lindenmaier, Goetz]

Hi,

I would like to downport this for parity with 11.0.6-oracle.

I had to resolve src/java.base/unix/native/libjava/TimeZone_md.c

In 14, data structure 'stat' was replaced by 'stat64'.
Also, some readdir64/readdir and dirent/dirent64 differ
in the contexts.

webrev: http://cr.openjdk.java.net/~goetz/wr19/8223490-optimize_time_zone-jdk11/01/
bug: https://bugs.openjdk.java.net/browse/JDK-8223490
orig change: https://hg.openjdk.java.net/jdk/jdk/rev/8ee083465318

Best regards,
  Goetz.