Remove libicuuc/libicui18n usage from art_gtest_defaults

Apparently, they are unused.

Bug: 138994281
Test: m art/test
Change-Id: I7add5d6970b08d9b6747449c0b45145cb17d38b5
diff --git a/test/Android.bp b/test/Android.bp
index db21339..6fc2fa4 100644
--- a/test/Android.bp
+++ b/test/Android.bp
@@ -65,8 +65,6 @@
         "libartbased",
 
         "libbase",
-        "libicuuc",
-        "libicui18n",
         "libnativehelper",
         "libz",
     ],