Merge pull request #65298 from nikhita/cherrypick-jsoniter-bump-1.9

Automatic merge from submit-queue.

Manual cherrypick of #65034 to 1.9: make json serializer case sensitive

fixes partially https://github.com/kubernetes/kubernetes/issues/64612

This PR imports the latest jsoniterator library so that case sensitivity during unmarshalling is optional. The PR also sets Kubernetes json serializer to be case sensitive.

**Release note**:

```release-note
ACTION REQUIRED: Kubernetes JSON deserializer is now case-sensitive to restore compatibility with pre-1.8 servers. If your config files contains fields with wrong case, the config files will be now invalid.
```

/sig api-machinery
/kind bug
/assign caesarxuchao liggitt thockin sttts mbohlool

Kubernetes-commit: f4cf484c2cb6056e28fb9759a3c913be3eed990a

vendor/github.com/json-iterator/go/pool.go

@@ -0,0 +1,42 @@
+package jsoniter
+
+import (
+	"io"
+)
+
+// IteratorPool a thread safe pool of iterators with same configuration
+type IteratorPool interface {
+	BorrowIterator(data []byte) *Iterator
+	ReturnIterator(iter *Iterator)
+}
+
+// StreamPool a thread safe pool of streams with same configuration
+type StreamPool interface {
+	BorrowStream(writer io.Writer) *Stream
+	ReturnStream(stream *Stream)
+}
+
+func (cfg *frozenConfig) BorrowStream(writer io.Writer) *Stream {
+	stream := cfg.streamPool.Get().(*Stream)
+	stream.Reset(writer)
+	return stream
+}
+
+func (cfg *frozenConfig) ReturnStream(stream *Stream) {
+	stream.out = nil
+	stream.Error = nil
+	stream.Attachment = nil
+	cfg.streamPool.Put(stream)
+}
+
+func (cfg *frozenConfig) BorrowIterator(data []byte) *Iterator {
+	iter := cfg.iteratorPool.Get().(*Iterator)
+	iter.ResetBytes(data)
+	return iter
+}
+
+func (cfg *frozenConfig) ReturnIterator(iter *Iterator) {
+	iter.Error = nil
+	iter.Attachment = nil
+	cfg.iteratorPool.Put(iter)
+}