Delete some old files

I think these are a relic of my attempt to create an optional API,
before we moved into the framework.

Deleting them doesn't seem to break anything.

Test: Still builds
Change-Id: Id78ea4b09645ae0bfd5c14d15bae545942421d4d

javalib/32/public/api/android.system.virtualmachine-removed.txt

@@ -1 +0,0 @@
-// Signature format: 2.0

javalib/32/public/api/android.system.virtualmachine.txt

@@ -1 +0,0 @@
-// Signature format: 2.0

javalib/32/system/api/android.system.virtualmachine-removed.txt

@@ -1 +0,0 @@
-// Signature format: 2.0

javalib/32/system/api/android.system.virtualmachine.txt

@@ -1 +0,0 @@
-// Signature format: 2.0

javalib/Android.bp

@@ -52,11 +52,6 @@ java_sdk_library {
     ],
 }
 
-prebuilt_apis {
-    name: "android-virtualization-framework-sdk",
-    api_dirs: ["32"],
-}
-
 java_api_contribution {
     name: "framework-virtualization-public-stubs",
     api_surface: "public",