Increase largest possible rebalance preference ratio

[NealSun96]

Issues

• My PR addresses the following Helix issues and references them in the PR description:

Fixes #1667

Description

• Here are some details about my PR, including screenshots of any UI changes:

For certain clusters, we need extreme evenness:movement ratio to obtain a good distribution. The current maximum ratio of 10:1 is not enough.

This PR increases the maximum weight to 1000 for these extreme cases.

Tests

• The following is the result of the "mvn test" command on the appropriate module:

[INFO] Tests run: 1265, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 5,096.014 s - in TestSuite
[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 1265, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  01:25 h
[INFO] Finished at: 2021-03-09T17:10:06-08:00
[INFO] ------------------------------------------------------------------------

Documentation (Optional)

• In case of new functionality, my PR adds documentation in the following wiki page:

(Link the GitHub wiki you added)

Commits

• My commits all reference appropriate Apache Helix GitHub issues in their subject lines. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters (not including Jira issue reference)
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

Code Quality

• My diff has been formatted using helix-style.xml
  (helix-style-intellij.xml if IntelliJ IDE is used)

[NealSun96]

This PR is ready to be merged, approved by @jiajunwang
Final commit message:

Increase largest possible rebalance preference ratio

This PR increases largest possible rebalance preference ratio by enlarging the maximum weight from 10 to 1000.