RFR: 8164669: Lazier initialization of java.time

[Claes Redestad]

Hi,

this tiny cleanup reduces number of loaded classes from a minimal test 
touching java.time.ZoneId.systemDefault() by ~40, by virtue of avoiding 
pulling in regex and some internal Calendar-related classes.

Bug: https://bugs.openjdk.java.net/browse/JDK-8164669
Webrev: http://cr.openjdk.java.net/~redestad/8164669/webrev.01/

Thanks!

/Claes