Apply SSA to array indices while preserving the original array dimension

1. Apply this transform to LHS array indexing for now. This strategy
will also be applied to all array indexing SSA transforms
2. Testcases
Simply array index SSA transform
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into newMaster
Merge pull request #1642 from junmendoza/newMaster

Apply SSA to array indices while preserving the original array dimension