[tools] reference comparison mode for rebalancing algo tests
[tools] reference comparison mode for rebalancing algo tests

Introduced comparison mode for rebalancing algorithms' tests.

For current rebalancing algorithms, it's natural to re-order contiguous
moves of the same weight. That's because of:
  * Iterating over elements of a hash container keyed by
    the weight of a move.
  * Randomly choosing among multiple options of the same weight.

This patch adds MovesOrderingComparison::IGNORE option into one test
configuration of the RebalanceAlgoUnitTest.LocationBalancingSimpleST
scenario.  That fixes the breakage of the test on Ubuntu 18.

Change-Id: I8363f013b5bf8caa3e3b967c64eccca95c763a91
Reviewed-on: http://gerrit.cloudera.org:8080/11870
Tested-by: Kudu Jenkins
Reviewed-by: Will Berkeley <c74686ab413a71926fc1bc9d16ebfa30e619336a@gmail.com>

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