RFR: 8296590: StraightLineTest fails always on Linux and sometimes on other platforms [v3]

[Jay Bhaskar]

> Issue: The test fails, in case snapshot is taken before web view finish web content load
> Solution: Introduce a sleep , before taking snapshot of web view , to test straight line

Jay Bhaskar has updated the pull request incrementally with one additional commit since the last revision:

  code cleanup for review comments

-------------

Changes:
  - all: https://git.openjdk.org/jfx/pull/1115/files
  - new: https://git.openjdk.org/jfx/pull/1115/files/87f672e5..82344b59

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1115&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1115&range=01-02

  Stats: 2 lines in 1 file changed: 0 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/1115.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1115/head:pull/1115

PR: https://git.openjdk.org/jfx/pull/1115