Cleanup Android.bp:framework-virtualization

There are a bunch of variables that are already set in the
framework-module-defaults, so there is no need to duplicate them.

Also disable the JavaApiUsedByMainlineModule check, since we are not an
updatable module we don't need it, and it's quite spammy.

As a side effect of this change our tests & demo apks need to compile
against framework-virtualization.impl library (which includes the hidden
APIs). Once the APIs are promoted to @SystemApi we can change the tests
to compile against framework-virtualization (which contains the API
stubs).

Bug: 243512044
Test: presubmit
Change-Id: Ib614d266f7a9cb8517afccd4feb737068b51fb20
diff --git a/tests/helper/Android.bp b/tests/helper/Android.bp
index bd92020..86af955 100644
--- a/tests/helper/Android.bp
+++ b/tests/helper/Android.bp
@@ -24,5 +24,8 @@
         "VirtualizationTestHelper",
         "truth-prebuilt",
     ],
-    libs: ["framework-virtualization"],
+    // We need to compile against the .impl library which includes the hidden
+    // APIs. Once the APIs are promoted to @SystemApi we can switch to
+    // framework-virtualization, which contains API stubs.
+    libs: ["framework-virtualization.impl"],
 }