Purge Ver3 dictionary writing in native code.

native/jni/Android.mk

...licyimpl/dictionary/bigram/dynamic_bigram_list_policy.cpp

...policyimpl/dictionary/bigram/dynamic_bigram_list_policy.h

...ionary/structure/v3/dynamic_patricia_trie_node_writer.cpp

...ctionary/structure/v3/dynamic_patricia_trie_node_writer.h

.../dictionary/structure/v3/dynamic_patricia_trie_policy.cpp

...pl/dictionary/structure/v3/dynamic_patricia_trie_policy.h

...ary/structure/v3/dynamic_patricia_trie_writing_helper.cpp

...onary/structure/v3/dynamic_patricia_trie_writing_helper.h

...nary/structure/v3/dynamic_patricia_trie_writing_utils.cpp

...ionary/structure/v3/dynamic_patricia_trie_writing_utils.h

...t/policyimpl/dictionary/utils/dict_file_writing_utils.cpp

...est/policyimpl/dictionary/utils/dict_file_writing_utils.h

...roid/inputmethod/latin/BinaryDictionaryDecayingTests.java

.../com/android/inputmethod/latin/BinaryDictionaryTests.java