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