Reduce log size from CountryTimeZones

ICU's TimeZone.toString() prints out too much information. Only the ID
is useful.

Bug: 149014708
Test: build only
Change-Id: I7d633f7946f82696e13dbc39749b6f9f44f83fa3

core/java/android/timezone/CountryTimeZones.java

@@ -140,7 +140,7 @@ public final class CountryTimeZones {
         @Override
         public String toString() {
             return "OffsetResult{"
-                    + "mTimeZone=" + mTimeZone
+                    + "mTimeZone(ID)=" + mTimeZone.getID()
                     + ", mIsOnlyMatch=" + mIsOnlyMatch
                     + '}';
         }