Move proguard before classes.jar

Downstream users of a library always link against javalib.jar, which
is either the dex jar for java libraries or a copy of
proguard.classes.jar for static java libraries.  In preparation for
making java libraries a superset of static java libraries, make
classes.jar always be the final class-containing jar for use
downstream, and always create a classes-pre-proguard.jar for
users that need a jar without shrinking or obfuscation.

Also rename the intermediates to be consitent: classes-<tool>.jar

Bug: 36902714
Test: m -j ANDROID_COMPILE_WITH_JACK=false java
Change-Id: I3df8b9a4edcd5db996f1fedc54c8a782d4f36a92
(cherry picked from commit 6fabefa8)