PackageManager lock reduction: IntentResolver

Bug: 161323622

Address two comments on the IntentResolver: doCopy() is renamed to
copyFrom() and WatchableIntentResolver.java is moved to be a peer of
IntentResolver.java.

Test: atest
 * FrameworksServicesTests:UserSystemPackageInstallerTest
 * FrameworksServicesTests:PackageManagerSettingsTests
 * FrameworksServicesTests:PackageManagerServiceTest
 * FrameworksServicesTests:AppsFilterTest
 * FrameworksServicesTests:PackageInstallerSessionTest
 * FrameworksServicesTests:ScanTests
 * FrameworksServicesTests:WatcherTest

Change-Id: I0b17c3e8531e3e1324f9ca93516237297f810c1e