go/types, types2: remove need to store type parameter list in unifier
For unification we only need the handles map.
The type parameter list was stored for reproducible printing only,
but we can achieve the same effect with sorting.
This opens the door to adding type parameters from different
types/functions that we may want to infer together. They may
be added through separate "addTypeParams" calls in the future.
Printing (which is used for debugging only) will remain reproducible.
Change-Id: I23b56c63fa45a7d687761f2efcf558e61b004584
Reviewed-on: https://go-review.googlesource.com/c/go/+/466955 Reviewed-by: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>