Automatic merge from submit-queue

fix naming for testgrid to pick up cmd test junit

Fixes #47613

The file name for testgrid to pick up should match regex `'junit(_[^_]+)?(_\d+-\d+)?(_\d+)?.xml'`
Name before is `junit-test-cmd.xml`
Name after is `junit_test-cmd.xml`

```release-note
NONE
```

/assign @krzyzacy