Re-implement native library search and copies.

We now use a two step approach :

- First we look through the list of shared libraries in an
  APK, and choose an ABI based on the (priority)  list of ABIs
  a given device supports.
- Then we look through the list of shared libraries and copy
  all shared libraries that match the ABI we've selected.

This fixes a long-standing bug where we would sometimes copy
a mixture of different ABIs to the device, and also allows us
to clearly pick an ABI to run an app with.

The code in NativeLibraryHelper has been refactored so that all
file name validation & matching logic is done in a single place
(NativeLibrariesIterator). This allows us to avoid a lot of
redundant logic and straightens out a few corner cases (for eg.
where the abi determination & copying logic do not agree on
what files to skip).

bug: https://code.google.com/p/android/issues/detail?id=65053


bug: 13647418

Change-Id: I34d08353f24115b0f6b800a7eda3ac427fa25fef
Co-Authored-By: Zhenghua Wang <zhenghua.wang0923@gmail.com>
Co-Authored-By: Ramin Zaghi <ramin.zaghi@arm.com>
Co-Authored-By: Narayan Kamath <narayan@google.com>