Revert "[DebugInfo][DAG] Distinguish different kinds of location indirection"
This reverts commit 3137fe4d23eeb8df08c03e9111465325eeafe08e.
The changes to dbg-value-func-arg.ll occur because our handling of certain
kinds of location now mixes up indirection that happens at different points
in a DIExpression. While this is a regression, it's a return to the prior
behaviour while a better patch is sought.