cmd/compile/internal/importer: drop support for indexed format
Drop support for the indexed format from the test-only Import
function.
Adds several TODOs for further tech debt reduction.
Change-Id: I45cc5ffce43082a145ccb918face067cdccc5ecd
Reviewed-on: https://go-review.googlesource.com/c/go/+/626695
Commit-Queue: Tim King <taking@google.com> Reviewed-by: Alan Donovan <adonovan@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Robert Findley <rfindley@google.com>