RFR: 8234071: JTable.AUTO_RESIZE_LAST_COLUMN acts like AUTO_RESIZE_ALL_COLUMNS [v3]

[Prasanta Sadhukhan]

> When a JTable is resized with` JTable.setAutoResizeMode` set to ` AUTO_RESIZE_LAST_COLUMN` then it behaves exactly as if I specified `AUTO_RESIZE_ALL_COLUMNS`. 
> This is because when `JTable.doLayout` tries to resize the columns, it checks which column to resize by calling `getResizingColumn `and in absence of any column info, it resizes all, so during `setAutoResizeMode` the resizing column needs to be set, which is being done for AUTO_RESIZE_LAST_COLUMN in this fix.
> No regression test is provided as it can be easily checked with SwingSet2->JTable(demo)->Autoresize mode (set to "Last Column")

Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:

  Get columnCount only once

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20107/files
  - new: https://git.openjdk.org/jdk/pull/20107/files/a441f380..6aa07353

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20107&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20107&range=01-02

  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/20107.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20107/head:pull/20107

PR: https://git.openjdk.org/jdk/pull/20107