Remove no longer meaningful upstream: true flag.

This used to direct robolectric tests to /external/robolectric rather than the older/unmaintained /external/robolectric-shadows, that has since been deleted.

Change-Id: If5065b2d25b5e5d8850f50dd4b25bd0ea7e3dd5c
Flag: TEST_ONLY
Test: CI
Bug: 386652866
diff --git a/tests/Android.bp b/tests/Android.bp
index f666bba..4bc654c 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -226,6 +226,5 @@
     ],
     instrumentation_for: "Launcher3",
     plugins: ["dagger2-compiler"],
-    upstream: true,
     strict_mode: false,
 }