Added a test to measure memory usage of apps.

Each app uses a certain amount of memory when running in the
foreground. This test takes a list of app on the command line
starts them one at a time and reports the total PSS of the
app's process. The test allows to monitor memory usage over time.

Change-Id: I3411bd96cf7c7af10acbb8deeb9936469b810ea2
4 files changed