Introduce TzDataSetVersion class

Introduce the TzDataSetVersion class to handle time
zone data and format versioning. It is a near-exact
copy of com.android.timezone.distro.DistroVersion
except that constants have been exposed as methods
to avoid inlining (important since the code using
this new class will not be updated when libcore code
is updated with new version requirements in future
versions of Android).

libcore.util is becoming increasingly filled with
time zone related classes so the new class is being
added in libcore.timezone.

Another easy-to-move class, TimeZoneDataFiles is being
moved there. Other time zone data-related classes
will be moved in follow-up changes.

Bug: 119026403
Test: CTS: run cts-dev -m CtsLibcoreTestCases
Change-Id: I57feae567e28950588062e5c67a954ed4f02462e
diff --git a/JavaLibrary.bp b/JavaLibrary.bp
index 6c2640c..1003883 100644
--- a/JavaLibrary.bp
+++ b/JavaLibrary.bp
@@ -681,3 +681,11 @@
     no_standard_libs: true,
     system_modules: "none",
 }
+
+// A host library containing time zone related classes. Used for
+// host-side tools and tests that have to deal with Android
+// time zone data.
+java_library_host {
+    name: "timezone-host",
+    srcs: [":timezone_host_files"],
+}