Always force constructors accessible during inflation

We now correctly throw an IllegalAccessException for non-public accesses,
but we were relying on the old incorrect behavior during inflation. This
CL forces constructors to be accessible so that we emulate the old
behavior and don't crash.

Where we were already doing this, the CL moves the setAccessible() call
immediately after the getConstructor() call, since there's no point in
calling it multiple times.

Bug: 20810495
Change-Id: I63dfcb857e445f688080eea05e86ef22760ed49f