Disable LoaderIntegrationTests when Docker's unavailable

Closes gh-29385

Author: wilkinsona

spring-boot-tests/spring-boot-integration-tests/spring-boot-loader-tests/src/intTest/java/org/springframework/boot/loader/LoaderIntegrationTests.java

@@ -33,6 +33,7 @@
 import org.testcontainers.utility.MountableFile;
 
 import org.springframework.boot.system.JavaVersion;
+import org.springframework.boot.testsupport.testcontainers.DisabledIfDockerUnavailable;
 import org.springframework.util.Assert;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -42,6 +43,7 @@
  *
  * @author Phillip Webb
  */
+@DisabledIfDockerUnavailable
 class LoaderIntegrationTests {
 
 	private final ToStringConsumer output = new ToStringConsumer();