Fix duplicate and dangling rules

I6730e2d3ec38004874265b2a690442dec57b33f4 introduced duplicate rules
to build classes.jar for static java library prebuilts, and left rules
to copy $(built_dex_intermediates) to $(built_dex) for modules that
don't build dex files.

Move prebuilts LOCAL_BUILT_MODULE back to javalib.jar to match
non-prebuilt modules, and remove the manual building of javalib.jar.

Add a check around $(built_dex_intermediates) for static java libraries.

Bug: 36901093
Test: m -j ANDROID_COMPILE_WITH_JACK=false
Change-Id: I291510b56162f0d35553e3c7ccd59b1382224d62