Replace the implementation of ICU.addLikelySubtags by ICU4J's implementation

- The method is only kept for @UnsupportedAppUsage

Test: libcore.libcore.icu.ICUTest#test_addLikelySubtags
Change-Id: Ic9d2d2880208e81bc6caf32795fb15685660c8d8
2 files changed