Copy PrettyPrintJSON to core framework

PrettyPrintJSON is most used e2emetrics function and that doesn't seem
specific for metrics. The implementation itself is generic, so it is
nice to move it to core framework for avoiding circular dependency.

test/e2e/framework/flake_reporting_util.go

@@ -20,8 +20,6 @@ import (
 	"bytes"
 	"fmt"
 	"sync"
-
-	e2emetrics "k8s.io/kubernetes/test/e2e/framework/metrics"
 )
 
 // FlakeReport is a struct for managing the flake report.
@@ -90,7 +88,7 @@ func (f *FlakeReport) PrintHumanReadable() string {
 func (f *FlakeReport) PrintJSON() string {
 	f.lock.RLock()
 	defer f.lock.RUnlock()
-	return e2emetrics.PrettyPrintJSON(f)
+	return PrettyPrintJSON(f)
 }
 
 // SummaryKind returns the summary of flake report.