Adds several tests and fixes export range bugs in the `StyledTextModel`. -------------
Commit messages: - lf - whitespace - fix - tests Changes: https://git.openjdk.org/jfx/pull/2029/files Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=2029&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8374909 Stats: 242 lines in 7 files changed: 198 ins; 30 del; 14 mod Patch: https://git.openjdk.org/jfx/pull/2029.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/2029/head:pull/2029 PR: https://git.openjdk.org/jfx/pull/2029
