Idea: Replace or enreach ParentFlags with actual stack of Expressions in the TryEmit methods to provide the full context

Instead of ParentFlags and Expression parameters in TryEmit... family of methods, add StackN (16) to CompilerContext. That way each emit level will know the exact context.
If required we may enrish each stack entry with some additiinal flag/info (only if required).
The impl should as efficient as posdible to avoid or better improve perf.
In addition, we minimize the number of paramsin TryEmit and centralize the access to the current (parent exprs) whick can be used to simplify plugin other types of expression, like FlatExpression in #463

Again, idea is to invormation from the expression stack (parent stack) Instead of ParentFlags. If it is bot fully possible, only then pass some additional flags/metadata.
Btw, we may also look if the parent expr stack removes the need for byRefIndex parameter.