Parallelize singleton execution

Bug: 281536768
Test: manual, presubmits
Change-Id: I57fdc76ba6b277e88e196b506af87127a530fd37
diff --git a/bloaty/bloaty.go b/bloaty/bloaty.go
index 50f241f..3cff60f 100644
--- a/bloaty/bloaty.go
+++ b/bloaty/bloaty.go
@@ -51,7 +51,7 @@
 	pctx.VariableConfigMethod("hostPrebuiltTag", android.Config.PrebuiltOS)
 	pctx.SourcePathVariable("bloaty", "prebuilts/build-tools/${hostPrebuiltTag}/bin/bloaty")
 	pctx.HostBinToolVariable("bloatyMerger", "bloaty_merger")
-	android.RegisterSingletonType("file_metrics", fileSizesSingleton)
+	android.RegisterParallelSingletonType("file_metrics", fileSizesSingleton)
 	fileSizeMeasurerKey = blueprint.NewProvider(measuredFiles{})
 }