Merge pull request #2076 from junmendoza/testcaseupdate

Testcase update for imperative
Code clean up for dead variable/properties/types
Merge pull request #2078 from ke-yu/code_cleanup

Code clean up for the core langauge
Revert "Code clean up for the core langauge"
Merge pull request #2080 from DynamoDS/revert-2078-code_cleanup

Revert "Code clean up for the core langauge"
Cross-lang testcase update