Fix regression on concrete playback inplace

[celinval]

Description of changes:

This fixes a regression from #2439. The compiler should store the location of the function body instead of the declaration. Storing the correct location fixes how concrete playback stores the generated unit test.

Resolved issues:

Resolves #2450

Related RFC:

Optional #ISSUE-NUMBER.

Call-outs:

I'm planning to add an end to end case to avoid regressions like this as we introduce the playback subcommand.

Testing:

• How is this change tested? Manually

• Is this a refactor change?

Checklist

• Each commit message has a non-empty body, explaining why the change was made
• Methods or procedures are documented
• Regression or unit tests are included, or existing tests cover the modified code
• My PR is restricted to a single feature or bugfix

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.

[jaisnan]

Thanks for the fix!