Wait for process to exit to avoid race with file deletion

See gh-25457

Author: wilkinsona

spring-boot-tests/spring-boot-integration-tests/spring-boot-server-tests/src/test/java/org/springframework/boot/context/embedded/AbstractApplicationLauncher.java

@@ -64,6 +64,12 @@ public void beforeEach(ExtensionContext context) throws Exception {
 	void destroyProcess() {
 		if (this.process != null) {
 			this.process.destroy();
+			try {
+				this.process.waitFor();
+			}
+			catch (InterruptedException ex) {
+				Thread.currentThread().interrupt();
+			}
 		}
 	}