net/url: add testable examples for url pkg funcs
net/url: add testable examples for url pkg funcs

Change-Id: I61011b75128478aa50308d84f4cba23b3e241b3f
Reviewed-on: https://go-review.googlesource.com/c/go/+/356536
Trust: Damien Neil <7e091e9a80da888fcd7836fd3c6b7b85f4677c12@google.com>
Trust: Cherry Mui <d62e63aa42ce272d7b6a5055d97e942b33a34679@google.com>
Run-TryBot: Damien Neil <7e091e9a80da888fcd7836fd3c6b7b85f4677c12@google.com>
TryBot-Result: Go Bot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Damien Neil <7e091e9a80da888fcd7836fd3c6b7b85f4677c12@google.com>

nawawi/go,golang/go,cloudflare/go,CAFxX/go,golang/go,nawawi/go,nawawi/go,golang/go,CAFxX/go,nawawi/go,cloudflare/go,CAFxX/go,nawawi/go,golang/go,cloudflare/go,CAFxX/go,golang/go,nawawi/go,golang/go,cloudflare/go,cloudflare/go,nawawi/go,nawawi/go,CAFxX/go,golang/go,cloudflare/go,CAFxX/go,CAFxX/go,CAFxX/go,golang/go,cloudflare/go,cloudflare/go