RFR: 8311031: JTable header border vertical lines are not aligned with data grid lines [v8]

[Tejesh R]

> The header border uses `g.drawLine` whereas the JTable data grid lines uses `SwingUtilities2.drawVLine` and `SwingUtilities2.drawHLine` to draw horizontal and vertical lines. The SwingUtilities2 uses `Graphics.fillRect` which contributes to the difference between the position of these two lines which happens/visible at higher ui scaling (difference in alignment between vertical lines of these two). The fix propose to use the same methods for metal L&F of JTable header border paint. 
> CI testing shows green.
> 
> ![image](https://github.com/openjdk/jdk/assets/94159358/f6d1d822-55ba-4ad3-9914-d3f68b67a6c5)

Tejesh R has updated the pull request incrementally with one additional commit since the last revision:

  Review fix

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/14766/files
  - new: https://git.openjdk.org/jdk/pull/14766/files/343915c4..d04dc7b0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14766&range=07
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14766&range=06-07

  Stats: 9 lines in 1 file changed: 2 ins; 2 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/14766.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14766/head:pull/14766

PR: https://git.openjdk.org/jdk/pull/14766