Use the same keyboard interrupt logic as run-tests.
Close the perf database explicitly after one run, as it has two runs on the same architecture. Currently the first run closes on garbage collection, which might corrupt the second run.

BUG=
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/284203002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21330 ce2b1a6d-e550-0410-aec6-3dcde31c8c00