Removed outdated TODO for LocaleList

The suggested TODO is no longer deemed necessary (and is too
expensive to do for all LocaleLists). LocaleLists get (and will get)
passed down to the native level through strings that are the result
of calls to toLanguageTags(), which is pre-computed at construction
time. Users who need to interact with the native level can do their
own caching, such as in commit
cfc607cf57.

Change-Id: I665f3b28eaf8df309bf1aec96f9d237aeb72865c

core/java/android/util/LocaleList.java

@@ -28,12 +28,6 @@ import com.android.internal.annotations.GuardedBy;
 import java.util.HashSet;
 import java.util.Locale;
 
-// TODO: We don't except too many LocaleLists to exist at the same time, and
-// we need access to the data at native level, so we should pass the data
-// down to the native level, create a map of every list seen there, take a
-// pointer back, and just keep that pointer in the Java-level object, so
-// things could be copied very quickly.
-
 /**
  * LocaleList is an immutable list of Locales, typically used to keep an
  * ordered user preferences for locales.