Automatic merge from submit-queue (batch tested with PRs 49581, 49652, 49681, 49688, 44655)
Add sig-testing OWNERS_ALIASES
/sig testing
**What this PR does / why we need it**:
follow the sig-foo-{reviewers,approvers} convention
- rename test-infra-maintainers to sig-testing-approvers
- copy sig-testing-approvers to sig-testing-reviewers
- remove inviduals in test/OWNERS in favor of new aliases
as a result
- rmmh gets test/ approver privileges
- spiffxp gets hack/jenkins/ approver privileges
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes#49580
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
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