Don't pre populate TimeZoneNames cache.

Stop pre populating the libcore.icu.TimeZoneNames cache, since no common
code path accesses it any more. The only public method that ends up
calling into this class is DateFormatSymbols.getZoneStrings().

Bug: 33259649
Test: run cts -m CtsLibcoreTestCases
Change-Id: I1c4ee8837dc7473277ef8d92be2ba2c165fd861d
1 file changed