Validation in shape functions of Dataset ops (#18680)

* Add shape check for PrependFromQueueAndPaddedBatchDataset

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Add comment for shape check

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Add shape check for FixedLengthRecordDataset

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Add check for filenames as well

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Clang-format -i --style=google for file format

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Add shape check for SqlDataset

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>