Improve parallelization of CSP and XSSAuditor reporting tests.

This patch passes the test name along with the report, meaning that each
test will write its own temporary file. This has the happy effect of
allowing us to run `http/tests/security` tests while providing the
`--fully-parallel` flag to the test runner.

Ah, speed.

Review URL: https://chromiumcodereview.appspot.com/23172003

git-svn-id: svn://svn.chromium.org/blink/trunk@156226 bbb929c8-8fbe-4397-9dbb-9b2b20218538