DO NOT MERGE Fix tests which relied on Pacific/Apia DST offset. [P-CTS]

java.util.TimeZone APIs allow to check offsets on specifc time, but
DateFormatSymbols always returns data as of now. So I've changed them to
be consistent with java.util.TimeZone.

Bug: 205971225
Bug: 207805859
Test: atest luni/src/test/java/libcore/java/test/DateFormatSymbolsTest.java
Test: atest luni/src/test/java/libcore/java/util/TimeZoneTest.java

Change-Id: I9e13e6c4552697957f8eb3e3b0327fe7d321bef9
Merged-In: I9e13e6c4552697957f8eb3e3b0327fe7d321bef9
2 files changed