Use test harness for image building integration tests

This commit modifies the integration tests for the Maven and Gradle
image building goal and task to use a custom builder as a test harness
to verify that the plugins invoke the builder as expected.

Fixes gh-25838

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootBuildImageIntegrationTests-buildsImageWithCommandLineOptions.gradle

@@ -0,0 +1,7 @@
+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+}
+
+sourceCompatibility = '1.8'
+targetCompatibility = '1.8'

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootBuildImageIntegrationTests-buildsImageWithCustomBuilderAndRunImage.gradle

@@ -8,6 +8,6 @@ targetCompatibility = '1.8'
 
 bootBuildImage {
 	imageName = "example/test-image-custom"
-	builder = "paketobuildpacks/builder:full"
-	runImage = "paketobuildpacks/run:full-cnb"
+	builder = "springci/spring-boot-cnb-builder:0.0.1"
+	runImage = "paketobuildpacks/run:tiny-cnb"
 }

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootBuildImageIntegrationTests-buildsImageWithCustomName.gradle

@@ -8,4 +8,5 @@ targetCompatibility = '1.8'
 
 bootBuildImage {
 	imageName = "example/test-image-name"
+	builder = "springci/spring-boot-cnb-builder:0.0.1"
 }

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootBuildImageIntegrationTests-buildsImageWithWarPackagingAndJarConfiguration.gradle

@@ -9,3 +9,7 @@ bootBuildImage {
 
 sourceCompatibility = '1.8'
 targetCompatibility = '1.8'
+
+bootBuildImage {
+	builder = "springci/spring-boot-cnb-builder:0.0.1"
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootBuildImageIntegrationTests-failsWithBuilderError.gradle

@@ -7,5 +7,6 @@ sourceCompatibility = '1.8'
 targetCompatibility = '1.8'
 
 bootBuildImage {
-	environment = ["BP_JVM_VERSION": "13.9.9"]
+	builder = "springci/spring-boot-cnb-builder:0.0.1"
+	environment = ["FORCE_FAILURE": "true"]
 }

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootBuildImageIntegrationTests.gradle

@@ -9,3 +9,7 @@ if (project.hasProperty('applyWarPlugin')) {
 
 sourceCompatibility = '1.8'
 targetCompatibility = '1.8'
+
+bootBuildImage {
+	builder = "springci/spring-boot-cnb-builder:0.0.1"
+}