Sharesheet - Cache loading of icons

For sharesheet, assume that the reordering of elements will make the
last assigned ViewHolder invalid for async icon loading. If we already
have an async task for the particular ResolveInfo, update the
ViewHolder target when it's complete.

Fixes: 158172791
Test: atest ChooserActivityTest ResolverActivityTest
Change-Id: I0ea9f443512f91e8fa4c5d6b72a35e9231e69e51