Simplify handling of ANDROID_JACK_* variables

This concerns ANDROID_JACK_VM, ANDROID_JACK_VM_ARGS and
ANDROID_JACK_EXTRA_ARGS.

Change-Id: Iba75ecaaceb09ac9607a3aee41324d9f5ae4beef
diff --git a/core/definitions.mk b/core/definitions.mk
index 56051bc..6ff62ed 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1752,7 +1752,7 @@
 else \
     export tmpEcjArg=""; \
 fi; \
-$(call call-jack,$(PRIVATE_JACK_VM),$(PRIVATE_JACK_VM_ARGS),$(PRIVATE_JACK_EXTRA_ARGS)) \
+$(call call-jack,$(PRIVATE_JACK_VM_ARGS),$(PRIVATE_JACK_EXTRA_ARGS)) \
     $(strip $(PRIVATE_JACK_FLAGS)) \
     $(strip $(PRIVATE_JACK_DEBUG_FLAGS)) \
     $(if $(NO_OPTIMIZE_DX), \
@@ -1785,7 +1785,7 @@
 	$(hide) mkdir -p $@.tmpjill.res
 	$(hide) $(call unzip-jar-files,$<,$@.tmpjill.res)
 	$(hide) find $@.tmpjill.res -iname "*.class" -delete
-	$(hide) $(call call-jack,$(PRIVATE_JACK_VM),$(PRIVATE_JACK_VM_ARGS),$(PRIVATE_JACK_EXTRA_ARGS)) \
+	$(hide) $(call call-jack,$(PRIVATE_JACK_VM_ARGS),$(PRIVATE_JACK_EXTRA_ARGS)) \
         -D jack.import.resource.policy=keep-first \
         -D jack.import.type.policy=keep-first \
 	    --import $@.tmpjill.jack \
@@ -1828,7 +1828,7 @@
 else \
     export tmpEcjArg=""; \
 fi; \
-$(call call-jack,$(PRIVATE_JACK_VM),$(PRIVATE_JACK_VM_ARGS),$(PRIVATE_JACK_EXTRA_ARGS)) \
+$(call call-jack,$(PRIVATE_JACK_VM_ARGS),$(PRIVATE_JACK_EXTRA_ARGS)) \
     $(strip $(PRIVATE_JACK_FLAGS)) \
     $(strip $(PRIVATE_JACK_DEBUG_FLAGS)) \
     $(if $(NO_OPTIMIZE_DX), \