New design for instant apps in app details header

Bug: 35098444
Test: make RunSettingsRoboTests

In the previous design for instant apps, some metadata about the app
such as developer title, maturity rating, etc. was going to be shown
in the app header. In the latest design, we instead are just showing
a little label that says "Instant app".

The two CL's for this topic work together to change this:

frameworks/base : adds code to work around the problem that
robolectric doesn't know about the new isInstantApp method of the
ApplicationInfo class, so we need to avoid calling it during tests.

pacakges/apps/Settings: removes the code that previously displayed
the instant app metadata, and instead just insert the "Instant app"
label.

Change-Id: Ie436085d4a257a1dd90b64d34d6ef15b8df369fd