net: allow single dot in resolv.conf search statement
A single dot in a search statement doesn't affect DNS lookup, so just ignore it and a syntax error.
Fixes #54124
Change-Id: Idd43bd34c5c16af50cba51f0b6e24f992eec6e57
Reviewed-on: https://go-review.googlesource.com/c/go/+/423875
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com> Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com>