[DSL] Fix the errorProne issues for the Helpers

[jswong65]

Fixes the errorProne issues introduced with the DSL Helper classes. All tests in DslTest are passed

• Removed redundant code for [HidingField] - HChain.java, VChain.java, Constraint.java
• Don't initialize the map to avoid [DoubleBraceInitialization] - Chain.java, Helper.java
• Added one more argument to avoid [InfiniteRecursion] (it's a bug) - VChain.java
• Added @SuppressWarnings("Finally") to suppress [Finally] - Ref.java