Parallelize singleton execution

Bug: 281536768
Test: manual, presubmits
Change-Id: I57fdc76ba6b277e88e196b506af87127a530fd37
diff --git a/snapshot/vendor_snapshot.go b/snapshot/vendor_snapshot.go
index 8f7b8c2..4484c85 100644
--- a/snapshot/vendor_snapshot.go
+++ b/snapshot/vendor_snapshot.go
@@ -78,8 +78,8 @@
 type VendorSnapshotImage struct{}
 
 func (VendorSnapshotImage) Init(ctx android.RegistrationContext) {
-	ctx.RegisterSingletonType("vendor-snapshot", VendorSnapshotSingleton)
-	ctx.RegisterSingletonType("vendor-fake-snapshot", VendorFakeSnapshotSingleton)
+	ctx.RegisterParallelSingletonType("vendor-snapshot", VendorSnapshotSingleton)
+	ctx.RegisterParallelSingletonType("vendor-fake-snapshot", VendorFakeSnapshotSingleton)
 }
 
 func (VendorSnapshotImage) RegisterAdditionalModule(ctx android.RegistrationContext, name string, factory android.ModuleFactory) {