Store AAR path from Soong for dist

Store the path to the AAR file from Soong so that it will be picked
up by dist if requested in TARGET_BUILD_APPS.

Test: m checkbuild
Change-Id: Ifeaf2b5ca3f405fbe79a966ceee9989a38d77f6e
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index 467637e..34a1db8 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -254,6 +254,7 @@
 LOCAL_SDK_VERSION:=
 LOCAL_SHARED_ANDROID_LIBRARIES:=
 LOCAL_SHARED_LIBRARIES:=
+LOCAL_SOONG_AAR :=
 LOCAL_SOONG_BUNDLE :=
 LOCAL_SOONG_CLASSES_JAR :=
 LOCAL_SOONG_DEX_JAR :=