Add data files for japanese subset

data/japanese/test.parquet

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:22004d249b712c5497b2497520a87bcc44acb9464ffb7ab83621454012ef6ea5
+size 261222135

data/japanese/train.parquet

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:41f96be6160000190403415b0a8e3b09d3433c22292c7cff5006bdadd19ed67e
+size 1865519583