Increase timeout on slow encrypted-media layout tests

The default timeout for tests using the w3c test harness is 2 seconds.
For several of these tests that play a little bit of video, this is not
long enough, especially when running using slower builds (like ASAN).
Setting the timeouts to a large value (60s) for both per-test time and
entire test time so that the infrastructure timeouts will be used.

BUG=353770, 353792
TEST=layout tests pass repeatedly using ASAN build

Review URL: https://codereview.chromium.org/205143002

git-svn-id: svn://svn.chromium.org/blink/trunk@169712 bbb929c8-8fbe-4397-9dbb-9b2b20218538