Remove the compat symlinks to ART binaries.

App compact impact is hard to judge (see http://b/124106384#comment9
ff), so this tries it early in the dessert cycle.

This is also a workaround for b/209867137 where the symlink install
rules interact badly with the artifact_path_requirements.mk check.

Test: m installclean && m droid
  verify that $(PRODUCT_DIR)/system/bin doesn't have dalvikvm and
  dex2oat symlinks
Bug: 124106384
Bug: 209867137
Change-Id: I044fb40f656beeb7c6e61f1d418fa13f56714a70