RFR: 8306083: Text.hitTest is incorrect when Text node is present in TextFlow [v2]

[Karthik P K]

> The text run selected in `PrismTextLayout::getHitInfo()` method for character index calculation was not correct when Text node was embedded in TextFlow. Hence wrong character index value was calculated for the same.
> 
> Since only x, y coordinates were available in the above mentioned method, sending the text as a parameter to this method is necessary so as to know if the text run selected for character index calculation is correct. Along with this change modified the `PrismTextLayout::getHitInfo()` method to calculate the correct character index.
> 
> Added tests to validate the changes.

Karthik P K has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains two commits:

 - Resolve merge conflict
 - Fix character index calculation issue in Text node embedded in TextFlow

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Changes: https://git.openjdk.org/jfx/pull/1157/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1157&range=01
  Stats: 372 lines in 7 files changed: 358 ins; 0 del; 14 mod
  Patch: https://git.openjdk.org/jfx/pull/1157.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1157/head:pull/1157

PR: https://git.openjdk.org/jfx/pull/1157