RFR: 8371070: RichParagraph enhancements

[Andy Goryachev]

Addressing the user feedback:

In RichParagraph you have a note to make getSegments() public.  It would be helpful if it was.


Adding two methods to the `RichParagraph` class:

- getSegmentCount()
- getSegment(int index)

Decided against exposing a List since it would require additional allocation.  Some of the callers seems to implement special logic when the number of segments is 0 anyway.

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Commit messages:
 - test
 - expose segments

Changes: https://git.openjdk.org/jfx/pull/1966/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1966&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8371070
  Stats: 213 lines in 7 files changed: 141 ins; 42 del; 30 mod
  Patch: https://git.openjdk.org/jfx/pull/1966.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1966/head:pull/1966

PR: https://git.openjdk.org/jfx/pull/1966