...which had already been conditional on U_ICU_VERSION_MAJOR_NUM > 51, so
452a06b7 "Activate unit test for Lao
breakiterator support" should merely have extended that #if to the function
declaration/definition in response to loplugin:unreffun, not unconditionally
enabled it.

Change-Id: Ia1ce4e99b4a960b1e70cae0a61b0d526b0353d9a