Set dist_group: "android" for libcore java_sdk_libraries

dist_group replaces owner and the default is going to change, set it
to the current default "android" for libcore java_sdk_libraries.

Bug: 186723288
Test: m checkbuild
Change-Id: Ida270c457106ef95544c8bdb48637a00ef57ce49
diff --git a/JavaLibrary.bp b/JavaLibrary.bp
index dcc89ca..0396096 100644
--- a/JavaLibrary.bp
+++ b/JavaLibrary.bp
@@ -949,6 +949,7 @@
     // the API will be checked for compatibility against the latest released
     // version of the API.
     dist_stem: "art",
+    dist_group: "android",
 }
 
 // Used when compiling higher-level code against art.module.public.api.stubs.