[Parameter Capturing] Import external code for il rewriting

[schmittjoseph]

Summary

Note: This is targeting a feature branch.

This PR imports code from the runtime repo relating to IL rewriting. Overview of commits:

• The first commit only contains a direct import of external code with no modifications.
• The second commit contains changes I've made to properly compile the new code and remove unnecessary code from ILRewriter.{cpp,.h} that won't be used.
• Everything afterwards are changes made during the PR process.

Release Notes Entry