Remove references to full_classes_proguard_jar

We always use R8 instead of proguard now, which shrinks while converting
to dex, so there is is no proguarded classes jar.  Use
full_classes_pre_proguard_jar instead.

Bug: 111885749
Test: m checkbuild
Change-Id: Ia0c35d9068b72573ae5970dc7e2c2b1b489b32f3