Silence errors when probing for AppCompat views

Currently, the only way that layoutlib has to detect if the support
library is a dependency of the project is to try to instantiate one of
the classes. In some cases, this might report errors that we do not want
the user to see since we will fall back to loading the non-appcompat
version.

Bug: http://b.android.com/218478
Change-Id: I064209f2c31d00c0cdfc9edb4cddec40e8e8f416
(cherry picked from commit 71dcc03353d4412231c8d8d0398ccdcad6c225d1)