Revert "Add $(PRODUCT_OUT)/apex to the artifact path whitelist"

This reverts commit 3387e656.

Reason for revert: Topic likely causing build failure on aosp_x86_64-eng in aosp_master:

"build/make/core/base_rules.mk:271: error: art/build/apex: MODULE.TARGET.SHARED_LIBRARIES.com.android.runtime.host.libart-compiler already defined by art/build/apex."

Change-Id: I2033828e7a13062b72d1d66a7f289cf5bb12b776