[SPARK-19059][SQL] Unable to retrieve data from parquet table whose name startswith underscore

## What changes were proposed in this pull request?
The initial shouldFilterOut() method invocation filter the root path name(table name in the intial call) and remove if it contains _. I moved the check one level below, so it first list files/directories in the given root path and then apply filter.
(Please fill in changes proposed in this fix)

## How was this patch tested?
Added new test case for this scenario
(Please explain how this patch was tested. E.g. unit tests, integration tests, manual tests)
(If this patch involves UI changes, please attach a screenshot; otherwise, remove this)

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Author: jayadevanmurali <jayadevan.m@tcs.com>
Author: jayadevan <jayadevan.m@tcs.com>

Closes #16635 from jayadevanmurali/branch-0.1-SPARK-19059.