This reverts commit 709387d660.
See https://issues.apache.org/jira/browse/SPARK-27300?focusedCommentId=16990048&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-16990048 and previous mailing list discussions.
### What changes were proposed in this pull request?
Revert the addition of skeleton graph API modules for Spark 3.0.
### Why are the changes needed?
It does not appear that content will be added to the module for Spark 3, so I propose avoiding committing to the modules, which are no-ops now, in the upcoming major 3.0 release.
### Does this PR introduce any user-facing change?
No, the modules were not released.
### How was this patch tested?
Existing tests, but mostly N/A.
Closes#26928 from srowen/Revert27300.
Authored-by: Sean Owen <srowen@gmail.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
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