addresses more PR feedbacks

1. Add Locals property to ILoopStatement
2. Remove IterationVariable from foreach loops and VB ForTo loops.
3. Add InvalidCondition to Do loops for VB error cases.
4. Rename property AddLoopBottomExpressionList to NextVariables
5. Add relevant unit tests
6. Remove ISyntheticLocalReferenceExpression and SyntheticLocalKind

Remove IsDeclaration: False from ILocalReferenceExpression and IFieldReferenceExpression. Adding back is tracked by #21798

Fixes #8882

1. Flatten the loop statement hierarchy to only derive from ILoopStatement
2. Separate out do loops and while loops
3. Separate out the C# and VB for loops due to different semantics and syntax.

Fixes #21282

Added deconstruction support, tests for IFieldReferenceExpression in out var and deconstruction script scenarios.