Remove test_com.android.neuralnetworks from apex_available

In order to simplify the apex logic in Soong, avoid needing to mention
test apexes in apex_available by setting apex_available_name in the
test apex to masquerade as the corresponding non-test apex.

Bug: 383592644
Test: builds
Change-Id: I143a9b51883a0724b1595cf3e7800709096f322f
diff --git a/neuralnetworks/aidl/Android.bp b/neuralnetworks/aidl/Android.bp
index 45b34e6..e7583aa 100644
--- a/neuralnetworks/aidl/Android.bp
+++ b/neuralnetworks/aidl/Android.bp
@@ -33,7 +33,6 @@
             apex_available: [
                 "//apex_available:platform",
                 "com.android.neuralnetworks",
-                "test_com.android.neuralnetworks",
             ],
             min_sdk_version: "30",
         },