ART: Store classpath information into oat file

Store a "dependency list" of class-path dex-files into the key-value
store of an oat file. The list is made up of dex locations and
corresponding checksums.

Add tests for encoding, decoding and checking the list.

Bug: 19781184
Change-Id: Ie700dd37e6e086db599c95d329ac1f1d2ff0b758