Reland "Remove Core Library JARs from /system/framework."

These JARs are part of the ART APEX, and are now located in
`/apex/com.android.art/javalib`. Remove the supernumerary copies in
`/system/framework` and save ~11 MiB on the system partition.

This change no longer breaks coverage builds, as module
`jacocoagent` has been removed from `TARGET_CORE_JARS` in CL
https://android-review.googlesource.com/c/platform/build/+/1151464.

This reverts commit 7c39368927.

Test: Device boot test
Test: Check that:
        export EMMA_INSTRUMENT=true
        && unset EMMA_INSTRUMENT_STATIC
        && m installclean
        && m systemimage
      generates a system image that contains these files:
        /system/framework/apex-jacocoagent.vdex
        /system/framework/boot-jacocoagent.vdex
        /system/framework/jacocoagent.jar
        /system/framework/<arch>/apex-jacocoagent.art
        /system/framework/<arch>/apex-jacocoagent.oat
        /system/framework/<arch>/apex-jacocoagent.vdex
        /system/framework/<arch>/boot-jacocoagent.art
        /system/framework/<arch>/boot-jacocoagent.oat
        /system/framework/<arch>/boot-jacocoagent.vdex
Test: Run test ATP test avd/avd_boot_health_check on build target
      cf_x86_phone-userdebug_coverage
Bug: 142944799
Bug: 143304991
Change-Id: Ifdb2331c5dcb992adbfd6c5a3983d8b9b13d16b2

CleanSpec.mk

@@ -695,6 +695,10 @@ $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/lib*/vndk-*)
 # Switch to symlinks for VNDK libs
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/lib*/vndk-*)
 
+# Remove Android Core Library artifacts from the system partition
+# again, as the original change removing them was reverted.
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/framework/*.jar)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************