cmd/compile: fix loclist for heap return vars without optimizations
When compiling without optimizations certain variables such as
return params end up missing location lists.
Fixes #65405
Change-Id: Id4ec6b1ab6681fd77b8fefb47a4ec05060c128ef
GitHub-Last-Rev:
5ab6a5398162119dd0cd5325f4239b4559b030bd
GitHub-Pull-Request: golang/go#74398
Reviewed-on: https://go-review.googlesource.com/c/go/+/684377
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>