Extracted static test utility methods from EditAndScrollTest into new VirtualizedControlTestUtils, added rudimentary tests for the methods.
------------- Commit messages: - 8278134: Move static utility methods to infrastructure Changes: https://git.openjdk.java.net/jfx/pull/690/files Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=690&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8278134 Stats: 348 lines in 3 files changed: 290 ins; 57 del; 1 mod Patch: https://git.openjdk.java.net/jfx/pull/690.diff Fetch: git fetch https://git.openjdk.java.net/jfx pull/690/head:pull/690 PR: https://git.openjdk.java.net/jfx/pull/690
