Increase CTS test recents panel timeout

Sometimes the recents panel launched by the test doesn't get closed, and
this causes subsequent tests to fail when the recents panel absorbs the
key events. Increase the timeout in hopes this will improve the
reliability.

Here is a log statement captured from a test that later tries to inject
the key event that the recents panel gets instead:

06-07 08:41:32.017   355   414 W InputDispatcher: Permission denied:
injecting event from pid 7944 uid 10052 to window Window{42600ff8
RecentsPanel paused=false} owned by uid 10042

Bug 6293866

Change-Id: I4c2a8e9a2f16de987021a693ed8e2df0f1fa8910