Increase logging in run-test 080-oom-throw to debug OOME-in-OOME issues.

Ensure the stack trace dumped before setting exception

  "java.lang.OutOfMemoryError: OutOfMemoryError thrown while trying
  to throw OutOfMemoryError; no stack trace available"

is displayed, by lowering the minimum log severity to WARNING for this
test.

Test: art/test/testrunner/testrunner.py --host -t 080-oom-throw
Bug: 77567088
Change-Id: I3d3ba310e672c9c56310653528f1c1b309a4bf55