net/url: fail TestParseErrors test when getting an unwanted error

The TestParseErrors test function was not strict with unwanted errors
received from url.Parse(). It was not failing in such cases, now it does.

Change-Id: I18a26a68c1136f5c762989a76e04b47e33dd35f1
GitHub-Last-Rev: c33f9842f7908f27012859e25caa79388cc2785a
GitHub-Pull-Request: golang/go#32954
Reviewed-on: https://go-review.googlesource.com/c/go/+/185080Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/net/url/url_test.go

@@ -1456,7 +1456,7 @@ func TestParseErrors(t *testing.T) {
 			continue
 		}
 		if err != nil {
-			t.Logf("Parse(%q) = %v; want no error", tt.in, err)
+			t.Errorf("Parse(%q) = %v; want no error", tt.in, err)
 		}
 	}
 }