Add a test API PackageManager#MODULE_APEX_NAME (2/n)

This API is used by the GTS to check mainline modules distributed as
apk-in-apex are included in the whitelist.

Bug: 148386485
Test: N/A (included in another CL)
Change-Id: I25b1c0703e3f345756a5ba91de070025042714f4

api/test-current.txt

@@ -917,6 +917,7 @@ package android.content.pm {
     field public static final int FLAG_PERMISSION_USER_SET = 1; // 0x1
     field public static final int MATCH_FACTORY_ONLY = 2097152; // 0x200000
     field public static final int MATCH_KNOWN_PACKAGES = 4202496; // 0x402000
+    field public static final int MODULE_APEX_NAME = 1; // 0x1
     field public static final String SYSTEM_SHARED_LIBRARY_SERVICES = "android.ext.services";
     field public static final String SYSTEM_SHARED_LIBRARY_SHARED = "android.ext.shared";
   }

core/java/android/content/pm/PackageManager.java

@@ -596,6 +596,7 @@ public abstract class PackageManager {
      * @hide
      */
     @SystemApi
+    @TestApi
     public static final int MODULE_APEX_NAME = 0x00000001;
 
     /** @hide */