Bump psutil from 5.9.5 to 5.9.8 in /tools

Bumps [psutil](https://github.com/giampaolo/psutil) from 5.9.5 to 5.9.8.
- [Changelog](https://github.com/giampaolo/psutil/blob/master/HISTORY.rst)
- [Commits](giampaolo/psutil@release-5.9.5...release-5.9.8)

---
updated-dependencies:
- dependency-name: psutil
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

tools/wptrunner/requirements_firefox.txt

@@ -6,5 +6,5 @@ mozleak==0.2
 mozprofile==3.0.0
 mozrunner==8.3.1
 mozversion==2.4.0
-psutil==5.9.5
+psutil==5.9.8
 redo==2.0.4

tools/wptrunner/requirements_safari.txt

@@ -1 +1 @@
-psutil==5.9.5
+psutil==5.9.8