Update location of pre-proguarded classes

In preparation for making java libraries usable as static java
libraries the classes.jar file is now the post-proguard output.
Depend on classes-pre-proguard.jar instead.

Non-static java library dependencies were using javalib.jar, which
contains classes.dex and is not what robolectric wants.  Move it
to depend on classes-pre-proguard.jar too.

Test: m -j RunSettingsRoboTests
Change-Id: I198563e0dca7bb0177ac4942b1da1c00b26d30a2