[ZEPPELIN-3075]Fix unqiue algo for the web side in pivot.js file.

[liguohui-lgh]

What is this PR for?

unique() algorithm is not correct in pivot.js file.
If the input is [2, 3, 3, 3, 4, 5] and the output will be [2, 3, 3, 4, 5]. The number 3 is still duplicated.

What type of PR is it?

[Bug Fix]

Todos

• - Task

What is the Jira issue?

https://issues.apache.org/jira/browse/ZEPPELIN-3075 [ZEPPELIN-3075]

How should this be tested?

Added unit test. Added screenshots for test.

Screenshots (if appropriate)

Questions:

• Does the licenses files need update? No
• Is there breaking changes for older versions? No
• Does this needs documentation? No

[tinkoff-dwh]

why another PR? #2685

[liguohui-lgh]

I don't know why the jenkins is failed for #2685.
The error tip is:

Looks like travis-ci is not configured for your fork.
Please setup by swich on 'zeppelin' repository at https://travis-ci.org/profile and travis-ci.

But my fork is copied from master. There is .travis.yml in the fork project.
I cannot find the commit message in https://travis-ci.org/profile and the JSON from https://api.travis-ci.org/repos/liguohuicmss/zeppelin/builds is empty.

[tinkoff-dwh]

close this PR.
read https://zeppelin.apache.org/contribution/contributions.html#continuous-integration
you should setting travis-ci to work with your fork (sign-in by Github, add repository (your fork))
after that your changes (in liguohuicmss:pivot-unqiue-algo) will start the build in travis-ci