[framework] Compile secondary dex files in isolation

The class loader context adds the overhead of extracting in-memory and
possibly extra verification which is being frowned upon when the loading
happens on the UI thread. Revert the correct fix of compiling secondary
dex files with their loading context until b/64530081 is done.

Partial revert of commit f1ff36f0.

Test: adb shell cmd package compile -m quicken -f --secondary-dex
com.google.android.gms
Bug: 64530081
Bug: 66984396
Change-Id: Ib2815ce67b224883fe95c28d1424103e56342c6e