Parallelize singleton execution

Bug: 281536768
Test: manual, presubmits
Change-Id: I57fdc76ba6b277e88e196b506af87127a530fd37
diff --git a/java/platform_bootclasspath.go b/java/platform_bootclasspath.go
index 07fb92c..0d4db7c 100644
--- a/java/platform_bootclasspath.go
+++ b/java/platform_bootclasspath.go
@@ -26,7 +26,7 @@
 }
 
 func registerPlatformBootclasspathBuildComponents(ctx android.RegistrationContext) {
-	ctx.RegisterSingletonModuleType("platform_bootclasspath", platformBootclasspathFactory)
+	ctx.RegisterParallelSingletonModuleType("platform_bootclasspath", platformBootclasspathFactory)
 }
 
 // The tags used for the dependencies between the platform bootclasspath and any configured boot