Ensure the invariant that “each syntax node has at most one corresponding explicit IOperation node” is met for all test scenarios we have at the moment. (#22894)

Related to #22229.

The following changes are made:
- Mark some synthesized bound nodes as compiler generated.
- Use correct syntax for a tuple on the left hand side of deconstruction.
- For throw statements, no longer add IExpressionStatementOperation on top of IThrowOperation node.
- For IInterpolatedStringText node, ensure the underlying ILiteralExpression is marked as implicit because it is sharing syntax node with its parent.

Address more feedback from design meeting and expose IOperation.IsExpression and IOperation.IsStatement properties

Fixes #22789

Microsoft.CodeAnalysis.Semantics renamed to Microsoft.CodeAnalysis.Operations

Addresses Preview and Documentation items from #22719

Fixes #22635

Fixes #22146

move designer attribute back to document level scanner but made it to use keep alive connection rather than creating new connection every time. also kept some optimization such as checking cps projects or not reporting as much as we can. (#22248)

* IDE Changes

* tests

* PR comments

Fixes #22272

* Add errors for ref-readonly signatures, readonly structs, and ref structs

* EE now working with ref-readonly

* Fix failing tests

* PR Comments