Unconditionally install com.android.virt APEX

The change in the packages/modules/Virtualization in the same topic
takes care for defining the right variant of the APEX to be installed:

* Devices with AVF support will get the full com.android.virt APEX
* Devices without AVF support will get an almost empty version that only
  contains an app that defines AVF-related permissions, and soon the BCP
  fragment jar.

Bug: 243512044
Test: build & flash oriole
Test: build & flash redfin
Change-Id: I2c38e03529a77dd2820212812433741725115ce0
diff --git a/core/product.mk b/core/product.mk
index 277fa74..dcfdf1f 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -367,6 +367,9 @@
 # BRANCH_DEFAULT_MODULE_BUILD_FROM_SOURCE but not an explicitly set value.
 _product_single_value_vars += PRODUCT_MODULE_BUILD_FROM_SOURCE
 
+# If true, installs a full version of com.android.virt APEX.
+_product_single_value_vars += PRODUCT_AVF_ENABLED
+
 .KATI_READONLY := _product_single_value_vars _product_list_vars
 _product_var_list :=$= $(_product_single_value_vars) $(_product_list_vars)