Add compat symlinks for prebuilt_apex

When prebuilt_apex overrides/replaces other apex, the same symlinks need
to be created as well.

Bug: 143192278
Test: 1. add prebuilt_apex with vndk apex
         with overrides set as ["com.android.vndk.current"]
      2. m <prebuilt apex>
      3. check if vndk symlinks are created

Change-Id: I8ee9c981ea9c7202ccf5143b3f43e6848773cd63
diff --git a/apex/apex.go b/apex/apex.go
index b27b54e..cd80503 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -522,9 +522,9 @@
 	manifestJsonOut android.WritablePath
 	manifestPbOut   android.WritablePath
 
-	// list of commands to create symlinks for backward compatibility
+	// list of commands to create symlinks for backward compatibility.
 	// these commands will be attached as LOCAL_POST_INSTALL_CMD to
-	// apex package itself(for unflattened build) or apex_manifest.json(for flattened build)
+	// apex package itself(for unflattened build) or apex_manifest(for flattened build)
 	// so that compat symlinks are always installed regardless of TARGET_FLATTEN_APEX setting.
 	compatSymlinks []string
 
@@ -1236,8 +1236,7 @@
 		a.buildUnflattenedApex(ctx)
 	}
 
-	apexName := proptools.StringDefault(a.properties.Apex_name, a.Name())
-	a.compatSymlinks = makeCompatSymlinks(apexName, ctx)
+	a.compatSymlinks = makeCompatSymlinks(a.BaseModuleName(), ctx)
 }
 
 func newApexBundle() *apexBundle {