RFR: 8017266: Background is painted taller than needed for styled text. [v3]

[Prasanta Sadhukhan]

> GlyphView.paint() draws background bounding the passed Shape, while the span reserved for the superscripted text is taller than the height of the glyphs so it is better to use the painter.getHeight() instead of alloc.height to fill the actual glyphs boundary
> 
> Before fix
> <img width="103" height="93" alt="image" src="https://github.com/user-attachments/assets/e673d214-13c7-4a42-8f55-cfd654e5a978" />
> 
> 
> With fix
> <img width="110" height="86" alt="image" src="https://github.com/user-attachments/assets/c13377a6-b4ac-406c-a153-a55c0b9a917b" />
> 
> No regressions is observed in CI..A manual verification test is provided..

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

  Use width, height

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27947/files
  - new: https://git.openjdk.org/jdk/pull/27947/files/ca92f16e..4c3ed865

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27947&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27947&range=01-02

  Stats: 7 lines in 1 file changed: 3 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/27947.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27947/head:pull/27947

PR: https://git.openjdk.org/jdk/pull/27947