RFR: 8282402: Create a regression test for JDK-4666101 [v2]

[Manukumar V S]

> Create a regression test for [JDK-4666101](https://bugs.openjdk.java.net/browse/JDK-4666101).
> 
> DESCRIPTION OF THE ACTUAL PROBLEM :
> In a JEditorPane, the down arrow has no effect after you add text on a line preceding a blank line.
> 
> Testing:
> As the original issue was reported in JDK 1.4.0 and it was fixed in JDK 1.4.2, I have verified the working of this test in those Java versions and the results are as follows:
> 
> Java 1.4.0 -> Test Failed.
> $ ./j2sdk1.4.0/bin/java JEditorBugWin
> Caret Updated : 3
> Test Failed, Down Arrow Key Not Functional, expected caret position is 5, but actual is 4
> 
> 
> Java 1.4.2 -> Test Passed.
> $ ./j2sdk1.4.2/bin/java JEditorBugWin
> Caret Updated : 5
> Test Passed, Down Arrow Key Functional

Manukumar V S has updated the pull request incrementally with one additional commit since the last revision:

  Take a screenshot when the test fails, helpful for debugging failures

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7623/files
  - new: https://git.openjdk.java.net/jdk/pull/7623/files/95148f72..5dec2a8a

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7623&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7623&range=00-01

  Stats: 18 lines in 1 file changed: 18 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7623.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7623/head:pull/7623

PR: https://git.openjdk.java.net/jdk/pull/7623