Make CtsPriv and CtsPrivShim build standalone.

Bug: 148489495
Test: build/soong/soong_ui.bash --make-mode -j80 showcommands dist TARGET_BUILD_APPS='CtsShim CtsShimPriv CtsShimPrivUpgrade CtsShimPrivUpgradeWrongSHA CtsShimTargetPSdk'  TARGET_BUILD_VARIANT=userdebug TARGET_PRODUCT=aosp_arm64
Change-Id: I1bd43b7ef9b4ebd5a24712306285c0ffd0e34d23
diff --git a/packages/CtsShim/build/Android.bp b/packages/CtsShim/build/Android.bp
index 8aac1c9..be79010 100644
--- a/packages/CtsShim/build/Android.bp
+++ b/packages/CtsShim/build/Android.bp
@@ -70,6 +70,7 @@
     // v2/v3 signature.
     use_embedded_native_libs: true,
     apex_available: [
+        "//apex_available:platform",
         "com.android.apex.cts.shim.v1",
         "com.android.apex.cts.shim.v2",
         "com.android.apex.cts.shim.v2_no_hashtree",
@@ -141,6 +142,7 @@
 
     manifest: "shim/AndroidManifest.xml",
     apex_available: [
+        "//apex_available:platform",
         "com.android.apex.cts.shim.v1",
         "com.android.apex.cts.shim.v2",
         "com.android.apex.cts.shim.v2_no_hashtree",