RFR: 8289751: Multiple unit test failures after JDK-8251483

[Marius Hanl]

As also discussed in the ticket, we need to disable/ignore this two tests for now.

With the fix for [JDK-8251483](https://bugs.openjdk.org/browse/JDK-8251483) the table row item is never null in a non empty table cell.
In the meantime with [JDK-8251480](https://bugs.openjdk.org/browse/JDK-8251480) and [JDK-8285197](https://bugs.openjdk.org/browse/JDK-8285197) we changed the table column header autosizing to be more complete by adding the table row to the setup.
Unfortunately we don't set the table view for the table row, therefore it can not know the underlying item (he knows the index but not where he can get the corresponding data for that index) -> table row item can be null in a non empty table cell (again).

This will be fixed in https://github.com/openjdk/jfx/pull/805 (and the tests can be reenabled)

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Commit messages:
 - Disabled currently failing tests

Changes: https://git.openjdk.org/jfx/pull/811/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=811&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8289751
  Stats: 3 lines in 2 files changed: 3 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/811.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/811/head:pull/811

PR: https://git.openjdk.org/jfx/pull/811