Fix two flaky media notification tests
There are two media notification tests flaky because of the test
pages are not set properly in BUILD.gn. This CL adds two test
pages in `media/session` test data directory so that they are
copied onto the device as they are executed. The `media/session`
test data directory is already in BUILD.gn so no changes there
needed.
BUG=697453
Review-Url: https://codereview.chromium.org/2722233002
Cr-Commit-Position: refs/heads/master@{#453991}
4 files changed
