reflect: omit anonymous field name from StructOf type string
This makes the reflect package match the compiler for StructOf
with an embedded field.
Fixes #24781
Change-Id: Ice64b167cbe0b9d30a953c5d8e2a86f3ad1158bf
Reviewed-on: https://go-review.googlesource.com/c/go/+/567897
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Keith Randall <khr@golang.org>
Commit-Queue: Ian Lance Taylor <iant@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>