* updated local decl

* put IVariableDeclarationStatement back to for loop before.

* put variable declaration syntax in variable declaration statement for for loop

* updated tests

* changed caller to call different APIs to create variable declaration when it can.

* changed to return IVaraibleDeclaration from CreateVariableDeclaration method

* addressed PR feedbacks

Fixes https://github.com/dotnet/roslyn/issues/21748

1. Fix test issues
2. Remove IHasDynamicArgumentsExpression interface and move the Arguments property from it to individual IDynamicXXXExpression nodes.
3. Adjust the extension methods for GetArgumentName and GetArgumentRefKind accordingly.

Address feedback from the design meeting and only expose the top level ITranslatedQueryExpression IOperation for v1.

We longer expose any special IOperation nodes for query clauses/operators, but just the underlying query plan. For v2, we hope to enhance the APIs to expose a richer query API.

Another design decision was to rewrite VB query lambdas into regular lambda, so we have parity between C# and VB operation trees.
This change refactors the VB query lambda local rewriting code to be consumed from the VB operation factory for the same.
The rewriter introduces a large number of DAGs, and we handle them in the operation factory rewriter by cloning the duplicate bound nodes in the lowered tree.

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

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

Fixes #20114 and #20122

* Tagging VB/C# Ioperation tests

* Fix the Wrong Tagging

Implements the proposal discussed in https://github.com/dotnet/roslyn/issues/17838#issuecomment-318125250.

1. We will have an `IQueryExpression` representing the topmost query expression.
2. This will point to the last query clause (`IQueryClause`) or continuation (`IQueryContinuation`) in the unrolled lowered bound tree - we are not got going to reverse the tree to match source.
3. `IQueryClause` will have a `QueryClauseKind` field indicating the type of query clause, which should match the syntax/language specification query clause/operator kinds.

* Expose if a Binary/Unary operator was 'Lifted' at the IExpression level.

* Update public API.

* Share computed value.

* Remove unnecessary extension.

* Update test code.

* Remove extension method.

* Fixup tests.

* Fixup tests.

* Fixup tests.

* Fix instances of Invalid operations with nullable

* Compound assignments also need to state if they're lifted.

* Move tests.

* Move tests.

* Move tests.

* Simplify comment.

* Case things consistently.

* Use F instead of Foo.  Because Foo is bad.

* Adding ioperation tests for ForEachStatement

* Addressing Feedback

* Removing Yield and nested tests

* Addressing PR feedback

* Fix breaking unit tests

* Adding ioperation tests for ForloopStatement

* Addressing the feedback