net/url: simplify values Get

Checking if v == nil is unnecessary, nil map always return the zero value of the value type.

Change-Id: I9c5499bc7db72c4c62e02013ba7f9a6ee4795c09
GitHub-Last-Rev: 03fc233
GitHub-Pull-Request: #58662
Reviewed-on: https://go-review.googlesource.com/c/go/+/470736
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
Reviewed-by: Than McIntosh <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>

Author: mateusz834

src/net/url/url.go

@@ -883,9 +883,6 @@ type Values map[string][]string
 // the empty string. To access multiple values, use the map
 // directly.
 func (v Values) Get(key string) string {
-	if v == nil {
-		return ""
-	}
 	vs := v[key]
 	if len(vs) == 0 {
 		return ""