Unifying non-incremental and incremental.

Step 1 moving all Incremental code into prepareDataLoaderLocked - where
non-incremental DataLoader calls reside.

Test: atest PackageManagerShellCommandTest
Bug: b/136132412 b/133435829 b/136132412
Change-Id: Icf670de6d4802bf52cd4a93fa4475629d9ac9bc0
2 files changed