The metrics of executor phase duration are not collected correctly

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)

query the metrics, eg `rate(tidb_executor_phase_duration_seconds_count[1m])` .

### 2. What did you expect to see? (Required)

There shoud have non-zero data.

### 3. What did you see instead (Required)

### 4. What is your TiDB version? (Required)

master