hg: jdk9/sandbox/jdk: 8066291: Return unmodifiable set of zone IDs to optimize ZoneIdPrinterParser

[chris.hegarty at oracle.com]

Changeset: b09d972a04da
Author:    bgopularam
Date:      2016-11-21 06:04 +0000
URL:       http://hg.openjdk.java.net/jdk9/sandbox/jdk/rev/b09d972a04da

8066291: Return unmodifiable set of zone IDs to optimize ZoneIdPrinterParser
Summary: Cache the available zones to speed up parsing
Reviewed-by: rriggs, scolebourne

! src/java.base/share/classes/java/time/ZoneId.java
! src/java.base/share/classes/java/time/zone/ZoneRulesProvider.java
! test/java/time/tck/java/time/zone/TCKZoneRulesProvider.java