go/types, types2: fix object path for grouped declaration statements
CL 715840 deferred popping from the object path during handling of
grouped declaration statements, which leaves extra objects on the
path since this executes in a loop.
Surprisingly, no test exercised this. This change fixes this small
bug and adds a supporting test.
Fixes #76366
Change-Id: I7fc038b39d3871eea3e60855c46614b463bcfa4f
Reviewed-on: https://go-review.googlesource.com/c/go/+/722060 Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Mark Freeman <markfreeman@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>