Polish "Remove unnecessary latches in tests"

Closes gh-16733

Author: wilkinsona

spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/env/DevToolsHomePropertiesPostProcessorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -73,9 +73,7 @@ public void ignoresMissingHomeProperties() throws Exception {
 	}
 
 	protected void runPostProcessor(Runnable runnable) throws Exception {
-		Thread thread = new Thread(() -> {
-			runnable.run();
-		});
+		Thread thread = new Thread(runnable);
 		thread.start();
 		thread.join();
 	}