removed bad import from test

Signed-off-by: Raza Jafri <rjafri@nvidia.com>

integration_tests/src/main/python/cast_test.py

@@ -16,7 +16,7 @@
 
 from asserts import assert_gpu_and_cpu_are_equal_collect, assert_gpu_and_cpu_are_equal_sql, assert_gpu_and_cpu_error, assert_gpu_fallback_collect, assert_py4j_exception
 from data_gen import *
-from spark_session import is_before_spark_320, with_gpu_session, is_neg_dec_scale_bug_version
+from spark_session import is_before_spark_320, with_gpu_session
 from marks import allow_non_gpu, approximate_float
 from pyspark.sql.types import *
 from spark_init_internal import spark_version