pkg: fix update calls to runtime.fastrand to use cheaprand for compatibility with Go 1.22 (#51672)

ref pingcap/tidb#50765

pkg/util/fastrand/BUILD.bazel

@@ -2,7 +2,11 @@ load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "fastrand",
-    srcs = ["random.go"],
+    srcs = [
+        "random.go",
+        "runtime.go",
+        "runtime_1.22.go",
+    ],
     importpath = "github.com/pingcap/tidb/pkg/util/fastrand",
     visibility = ["//visibility:public"],
 )

pkg/util/fastrand/random.go

@@ -16,7 +16,6 @@ package fastrand
 
 import (
 	"math/bits"
-	_ "unsafe" // required by go:linkname
 )
 
 // wyrand is a fast PRNG. See https://github.com/wangyi-fudan/wyhash
@@ -48,11 +47,6 @@ func Buf(size int) []byte {
 	return buf
 }
 
-// Uint32 returns a lock free uint32 value.
-//
-//go:linkname Uint32 runtime.fastrand
-func Uint32() uint32
-
 // Uint32N returns, as an uint32, a pseudo-random number in [0,n).
 func Uint32N(n uint32) uint32 {
 	// This is similar to Uint32() % n, but faster.

pkg/util/fastrand/runtime.go

@@ -0,0 +1,26 @@
+// Copyright 2024 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !go1.22
+
+package fastrand
+
+import (
+	_ "unsafe" // required by go:linkname
+)
+
+// Uint32 returns a lock free uint32 value.
+//
+//go:linkname Uint32 runtime.fastrand
+func Uint32() uint32

pkg/util/fastrand/runtime_1.22.go

@@ -0,0 +1,26 @@
+// Copyright 2024 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build go1.22
+
+package fastrand
+
+import (
+	_ "unsafe" // required by go:linkname
+)
+
+// Uint32 returns a lock free uint32 value.
+//
+//go:linkname Uint32 runtime.cheaprand
+func Uint32() uint32