RFR: 8302797: ArrayIndexOutOfBoundsException in TextRun.getWrapIndex()

[Phil Race]

This fixes an the AIOOBE when finding a line break point in RTL laid out glyphs.
The comment in the bug report explains how we can end up trying to find an unachievable break point and yet there's no "stop" on the search when we've run out of glyphs so hence the exception.

The fix uses a different method to choose a break point.

A system test has been supplied which will fail on macOS (even with standard macOS fonts, not just the Noto Sans Arabic) unless the fix is applied.

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Commit messages:
 - 8302797

Changes: https://git.openjdk.org/jfx/pull/1055/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1055&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8302797
  Stats: 221 lines in 2 files changed: 214 ins; 5 del; 2 mod
  Patch: https://git.openjdk.org/jfx/pull/1055.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/1055/head:pull/1055

PR: https://git.openjdk.org/jfx/pull/1055