Add go profile instrumentation to kubectl

This commit adds two new global options to kubectl: --profile and
--profile-output, writing out go profiles to disk to debug interesting and
unexpected kubectl behaviour.

As an example, here is how to capture a block file, eg. for how long are we
blocked on I/O and where?

$ kubectl get nodes --profile=mutex -v6
$ go tool pprof -png ./profile.pprof > out.png
$ google-chrome out.png

Fixes: #68679

pkg/kubectl/cmd/cmd.go

@@ -370,6 +370,14 @@ func NewKubectlCommand(in io.Reader, out, err io.Writer) *cobra.Command {
       Find more information at:
             https://kubernetes.io/docs/reference/kubectl/overview/`),
 		Run: runHelp,
+		// Hook before and after Run initialize and write profiles to disk,
+		// respectively.
+		PersistentPreRunE: func(*cobra.Command, []string) error {
+			return initProfiling()
+		},
+		PersistentPostRunE: func(*cobra.Command, []string) error {
+			return flushProfiling()
+		},
 		BashCompletionFunction: bashCompletionFunc,
 	}
 
@@ -380,6 +388,8 @@ func NewKubectlCommand(in io.Reader, out, err io.Writer) *cobra.Command {
 	// a.k.a. change all "_" to "-". e.g. glog package
 	flags.SetNormalizeFunc(utilflag.WordSepNormalizeFunc)
 
+	addProfilingFlags(flags)
+
 	kubeConfigFlags := genericclioptions.NewConfigFlags()
 	kubeConfigFlags.AddFlags(flags)
 	matchVersionKubeConfigFlags := cmdutil.NewMatchVersionFlags(kubeConfigFlags)