go/types, types2: in struct processing, set name position in types2
As a consequence, the positions needed by the Checker.structType
internal helper functions add and addInvalid are always the positions
of the provided identifiers, and we can leave away the extra position
arguments.
Change-Id: Iddc275c83d3781261476b8e1903050e0a049957c
Reviewed-on: https://go-review.googlesource.com/c/go/+/558316
Run-TryBot: Robert Griesemer <gri@google.com> Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Robert Griesemer <gri@google.com>