all: remove Go 1.17 build tags / workarounds

related to golang/protobuf#1613

Change-Id: Ie4255c24c1b79b13aab763a75125836191088d26
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/585096
Reviewed-by: Lasse Folger <lassefolger@google.com>
Auto-Submit: Michael Stapelberg <stapelberg@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

encoding/protojson/fuzz_test.go

@@ -2,10 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Go native fuzzing was added in go1.18. Remove this once we stop supporting
-// go1.17.
-//go:build go1.18
-
 package protojson_test
 
 import (

encoding/prototext/fuzz_test.go

@@ -2,10 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Go native fuzzing was added in go1.18. Remove this once we stop supporting
-// go1.17.
-//go:build go1.18
-
 package prototext_test
 
 import (

integration_test.go

@@ -18,7 +18,6 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"reflect"
 	"regexp"
 	"runtime"
 	"runtime/debug"
@@ -560,15 +559,9 @@ func race() bool {
 	if !ok {
 		return false
 	}
-	// Use reflect because the debug.BuildInfo.Settings field
-	// isn't available in Go 1.17.
-	s := reflect.ValueOf(bi).Elem().FieldByName("Settings")
-	if !s.IsValid() {
-		return false
-	}
-	for i := 0; i < s.Len(); i++ {
-		if s.Index(i).FieldByName("Key").String() == "-race" {
-			return s.Index(i).FieldByName("Value").String() == "true"
+	for _, setting := range bi.Settings {
+		if setting.Key == "-race" {
+			return setting.Value == "true"
 		}
 	}
 	return false

proto/fuzz_test.go

@@ -2,10 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Go native fuzzing was added in go1.18. Remove this once we stop supporting
-// go1.17.
-//go:build go1.18
-
 package proto_test
 
 import (