[SPARK-9827] [SQL] fix fd leak in UnsafeRowSerializer

Currently, UnsafeRowSerializer does not close the InputStream, will cause fd leak if the InputStream has an open fd in it.

TODO: the fd could still be leaked, if any items in the stream is not consumed. Currently it replies on GC to close the fd in this case.

cc JoshRosen

Author: Davies Liu <davies@databricks.com>

Closes #8116 from davies/fd_leak.