RFR: 8282093: LineChart path incorrect when outside lower bound

[Abhinay Agarwal]

This regression was caused in PR #667 in which I didn't take into account the lower bounds. I have added more tests and one manual test along with the fix. The manual test can be used to identify any future issues with paths outside lower and upper bounds easily.

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Commit messages:
 - remove extraneous whitespace
 - 8282093: LineChart path incorrect when outside lower bound

Changes: https://git.openjdk.java.net/jfx/pull/744/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=744&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8282093
  Stats: 509 lines in 4 files changed: 486 ins; 0 del; 23 mod
  Patch: https://git.openjdk.java.net/jfx/pull/744.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/744/head:pull/744

PR: https://git.openjdk.java.net/jfx/pull/744