Introduces Region.snapInnerSpaceX/Y() methods for dealing with inner space (using Math.floor), see for instance [JDK-8299753](https://bugs.openjdk.org/browse/JDK-8299753), using existing methods Region.snapPortionX/Y().
------------- Commit messages: - tests - Merge remote-tracking branch 'origin/master' into ag.8311527.snap.inner - javadoc - snap portion - cleanup - 8311527: snap inner space Changes: https://git.openjdk.org/jfx/pull/1190/files Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1190&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8311527 Stats: 88 lines in 2 files changed: 87 ins; 0 del; 1 mod Patch: https://git.openjdk.org/jfx/pull/1190.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/1190/head:pull/1190 PR: https://git.openjdk.org/jfx/pull/1190
