RFR: 8311127: Regression: The fix for TableView and TreeTableView menu button affects all table column headers

[Jose Pereda]

This PR fixes the regression introduced with [JDK-8087673](https://bugs.openjdk.org/browse/JDK-8087673) by only modifying the header's width if it is the last visible column.

Two tests that fail before the proposed patch and pass after it have been also included.

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Commit messages:
 - update license header
 - Only modify header's width if it is the last visible column, and include tests

Changes: https://git.openjdk.org/jfx/pull/1166/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1166&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8311127
  Stats: 101 lines in 3 files changed: 99 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jfx/pull/1166.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1166/head:pull/1166

PR: https://git.openjdk.org/jfx/pull/1166