Remove unused methods.

native/jni/Android.mk

...ve/jni/com_android_inputmethod_latin_BinaryDictionary.cpp

native/jni/src/obsolete/correction.cpp

native/jni/src/obsolete/correction.h

native/jni/src/obsolete/correction_state.h

native/jni/src/suggest/core/dictionary/bigram_dictionary.cpp

native/jni/src/suggest/core/dictionary/bigram_dictionary.h

native/jni/src/suggest/core/dictionary/binary_format.h

native/jni/src/suggest/core/dictionary/probability_utils.h

native/jni/src/suggest/core/layout/proximity_info.h

native/jni/src/suggest/core/layout/proximity_info_state.cpp

native/jni/src/suggest/core/layout/proximity_info_state.h

...ni/src/suggest/core/layout/proximity_info_state_utils.cpp

...src/suggest/core/layout/touch_position_correction_utils.h

native/jni/src/suggest/policyimpl/utils/edit_distance.h

native/jni/src/utils/autocorrection_threshold_utils.cpp

native/jni/src/utils/autocorrection_threshold_utils.h