gardening: mark 2 jquery tests as slow, npruntime/throw-exception.html as flaky
gardening: mark 2 jquery tests as slow, npruntime/throw-exception.html as flaky

TBR=esprehn@chromium.org
BUG=255407

Review URL: https://codereview.chromium.org/18184003

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@153223 bbb929c8-8fbe-4397-9dbb-9b2b20218538

primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs