Directly support value converters and comparers that reference only a static expression method

[ajcvickers]

That is, more than just passing an expression for the method call to the ValueConverter constructor.

[ajcvickers]

See #32659

[roji]

Also comparers?

[AndriySvyryd]

Related to #32717

As for the implementation, we can determine when to generate a static method for a given Expression by calling a new ILinqToCSharpSyntaxTranslator.Translate method that would return either a StatementSyntax or ExpressionSyntax.