core: Move core.oat bootjar definitions into envsetup.mk

TARGET_CORE_JARS and HOST_CORE_JARS define the minimal
bootclasspath jars necessary to run with dalvikvm/art.

Also refactor PRODUCT_BOOT_JARS in core-tiny.mk and core-minimal.mk
to reuse TARGET_CORE_JARS.

The above variables can be used from scripts with get_build_var
from envsetup.sh

  $> get_build_var TARGET_CORE_JARS
  <prints list of core jars>

(These changes are required to figure out what --bootclasspath_entry
to pass to desugar).

Bug: 36902714
Test: make -j32 build-art-host build-art-target
Test: lunch aosp_angler-userdebug && make -j32
Test: make -j32 PRODUCT-sdk_google_aw_x86-sdk
Merged-In: If12569719343bfbba20c1cda9a5302ab541dbfc6
Change-Id: If12569719343bfbba20c1cda9a5302ab541dbfc6
4 files changed