This new function, although different in signature from other
reflect functions, allows the caller to avoid the panic caused by
nil embedded fields in calls to FieldByIndex.
Fixes #48218
Change-Id: I447f135bb789148c27ae3f2f23dcf43094f4c1de
Reviewed-on: https://go-review.googlesource.com/c/go/+/357962
Trust: Rob Pike <r@golang.org>
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>