Use unique apex variations for bootclasspath fragments

Upcoming changes to the ApexInfo mutator will require unique apex
variations for the bootclasspath fragments, change them now to simplify
comparisons.

Test: go test ./...
Change-Id: Ia8880fe5ac22a7bd2fb9ddaeb3b04b9ae90b1701
diff --git a/java/systemserver_classpath_fragment.go b/java/systemserver_classpath_fragment.go
index 3176ad9..f3074ed 100644
--- a/java/systemserver_classpath_fragment.go
+++ b/java/systemserver_classpath_fragment.go
@@ -58,6 +58,10 @@
 	return m
 }
 
+func (m *platformSystemServerClasspathModule) UniqueApexVariations() bool {
+	return true
+}
+
 func (p *platformSystemServerClasspathModule) AndroidMkEntries() (entries []android.AndroidMkEntries) {
 	return p.classpathFragmentBase().androidMkEntries()
 }
@@ -115,6 +119,9 @@
 	android.InitAndroidArchModule(m, android.DeviceSupported, android.MultilibCommon)
 	return m
 }
+func (m *SystemServerClasspathModule) UniqueApexVariations() bool {
+	return true
+}
 
 func (s *SystemServerClasspathModule) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	if len(s.properties.Contents.GetOrDefault(ctx, nil)) == 0 && len(s.properties.Standalone_contents.GetOrDefault(ctx, nil)) == 0 {