fix: move OOV test cases out of shared test data to fix C++ unit tests (#370)

The C++ runtime test loads test data from normalizer.txt but uses FSTs
built without tag_oov=True. OOV test cases (Korean/Japanese characters)
that require <oov> wrapping are moved to a separate file only loaded by
the Python test (which uses tag_oov=True).

Fixes #368

Author: pengzhendong

tn/chinese/test/data/normalizer.txt

@@ -35,8 +35,6 @@
 我儿子喜欢这地儿 => 我儿子喜欢这地
 O2O => O to O
 B2B => B to B
-我们안녕 => 我们<oov>안</oov><oov>녕</oov>
-雪の花 => 雪<oov>の</oov>花
 给12315打个电话 => 给幺二三幺五打个电话
 人均200以内 => 人均两百以内
 当场票数≥100万 => 当场票数大于等于一百万

tn/chinese/test/data/normalizer_tag_oov.txt

@@ -0,0 +1,2 @@
+我们안녕 => 我们<oov>안</oov><oov>녕</oov>
+雪の花 => 雪<oov>の</oov>花

tn/chinese/test/normalizer_test.py

@@ -34,6 +34,7 @@ class TestNormalizer:
         parse_test_case("data/time.txt"),
         parse_test_case("data/whitelist.txt"),
         parse_test_case("data/normalizer.txt"),
+        parse_test_case("data/normalizer_tag_oov.txt"),
     )
 
     @pytest.mark.parametrize("written, spoken", normalizer_cases)