Tracking Issue: Initialize AST types using helper methods

[arvind-murty]

Description

Currently, there is very little support for initializing AST types using helper methods. As such, interaction with the AST is typically done by creating the types and modifying the variables directly. The goal of this issue is to make progress towards interacting with the AST primarily using helper methods.

Related Issues and PRs

PR #13260 - Creation of a handful of initialization methods in ast_funcs.go