Introduce droidcore-unbundled target

The droidcore-unbundled target replaces the droidcore
target when TARGET_BUILD_UNBUNDLED_IMAGE=true. This
target is similar to droidcore in terms of dependencies,
but it has a smaller set of dist files. The intention is
to use TARGET_BUILD_UNBUNDLED_IMAGE=true with a
VSDK-using vendor build to supply Java dependencies from
prebuilts to avoid building (or needing) Java framework
sources.

Test: build with and without TARGET_BUILD_UNBUNDLED_IMAGE=true
Test: m nothing dist (before patch)
Test: m nothing dist (after patch)
Test: m nothing dist TARGET_BUILD_UNBUNDLED_IMAGE=true (after patch)
Test: examine ninja build graph for previous 3 tests
Bug: 188176942
Bug: 187064252
Change-Id: Ia7f8200c1bb1aaaa57c177d1698a114efe26bec7
(cherry picked from commit 0a30cc41bc)

core/tasks/collect_gpl_sources.mk

@@ -26,4 +26,4 @@ $(gpl_source_tgz) : $(ALL_GPL_MODULE_LICENSE_FILES)
 	$(hide) tar cfz $@ --exclude ".git*" $(PRIVATE_PATHS)
 
 # Dist the tgz only if we are doing a full build
-$(call dist-for-goals,droidcore,$(gpl_source_tgz))
+$(call dist-for-goals,droidcore-unbundled,$(gpl_source_tgz))

core/tasks/host_init_verifier.mk

@@ -53,4 +53,4 @@ $(host_init_verifier_output): $(HOST_INIT_VERIFIER)
 		--out_product $(PRODUCT_OUT)/$(TARGET_COPY_OUT_PRODUCT) \
 		> $@
 
-$(call dist-for-goals,droidcore,$(host_init_verifier_output))
+$(call dist-for-goals,droidcore-unbundled,$(host_init_verifier_output))

core/tasks/module-info.mk

@@ -26,7 +26,7 @@ $(MODULE_INFO_JSON):
 	$(hide) echo '}' >> $@
 
 
-droidcore: $(MODULE_INFO_JSON)
+droidcore-unbundled: $(MODULE_INFO_JSON)
 
 $(call dist-for-goals, general-tests, $(MODULE_INFO_JSON))
-$(call dist-for-goals, droidcore, $(MODULE_INFO_JSON))
+$(call dist-for-goals, droidcore-unbundled, $(MODULE_INFO_JSON))