performDexOptLibsLI and related methods were extracted to PackageDexOptimizer class. Minor refactoring of PackageManagerService. This is a non-functional change. It should simplify further work to allow storing OAT files inside package dir. (cherry picked from commit eeea67b8c3678d882d3774edc41242c63daa60fa) Change-Id: I3494a2da70605362bb6fb4625ffbee1cbe1cd457