Fix chaindatafetcher API

Fix this error

```
panic: interface conversion: interface {} is json.RawMessage, not *vm.InternalTxTrace

goroutine 936 [running]:
github.com/klaytn/klaytn/datasync/chaindatafetcher.(*ChainDataFetcher).makeChainEvent(0xc08a357900, 0x4c4b401)
        /home/ec2-user/kaia/datasync/chaindatafetcher/chaindata_fetcher.go:323 +0xb30
github.com/klaytn/klaytn/datasync/chaindatafetcher.(*ChainDataFetcher).handleRequest(0xc08a357900)
        /home/ec2-user/kaia/datasync/chaindatafetcher/chaindata_fetcher.go:476 +0x1f4
created by github.com/klaytn/klaytn/datasync/chaindatafetcher.(*ChainDataFetcher).Start in goroutine 1
        /home/ec2-user/kaia/datasync/chaindatafetcher/chaindata_fetcher.go:174 +0x25
```

blockchain/vm/call_tracer.go

@@ -58,7 +58,7 @@ func (f CallFrame) ToInternalTxTrace() *InternalTxTrace {
 	t.From = &f.From
 	t.To = f.To
 	if f.Value != nil {
-		t.Value = f.Value.Text(16)
+		t.Value = "0x" + f.Value.Text(16)
 	}
 
 	t.Gas = f.Gas
@@ -220,7 +220,16 @@ func (t *CallTracer) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost, ccL
 func (t *CallTracer) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost, ccLeft, ccOpcode uint64, scope *ScopeContext, depth int, err error) {
 }
 
-func (t *CallTracer) GetResult() (json.RawMessage, error) {
+func (t *CallTracer) GetResult() ([]CallFrame, error) {
+	if len(t.callstack) != 1 {
+		return nil, errors.New("incorrect number of top-level calls")
+	}
+
+	// Return with interrupt reason if any
+	return t.callstack, t.interruptReason
+}
+
+func (t *CallTracer) GetResultAsJson() (json.RawMessage, error) {
 	if len(t.callstack) != 1 {
 		return nil, errors.New("incorrect number of top-level calls")
 	}

datasync/chaindatafetcher/chaindata_fetcher.go

@@ -320,7 +320,11 @@ func (f *ChainDataFetcher) makeChainEvent(blockNumber uint64) (blockchain.ChainE
 		}
 		for _, r := range results {
 			if r.Result != nil {
-				internalTraces = append(internalTraces, r.Result.(*vm.InternalTxTrace))
+				switch r.Result.(type) {
+				case []vm.CallFrame:
+					cf := r.Result.([]vm.CallFrame)
+					internalTraces = append(internalTraces, cf[0].ToInternalTxTrace())
+				}
 			} else {
 				traceAPIErrorCounter.Inc(1)
 				logger.Error("the trace result is nil", "err", r.Error, "blockNumber", blockNumber)

node/cn/tracers/tracers_test.go

@@ -170,7 +170,7 @@ func runTracer(t *testing.T, tc *tracerTestdata, tracer vm.Tracer) (*types.Trans
 	case *Tracer:
 		tracerResult, err = tracer.GetResult()
 	case *vm.CallTracer:
-		tracerResult, err = tracer.GetResult()
+		tracerResult, err = tracer.GetResultAsJson()
 	}
 	require.NoError(t, err)
 	assert.JSONEq(t, string(tc.Result), string(tracerResult))