Ensure Gradle tasks are configured lazily

At present, generated Gradle build scripts that use Groovy DSL configure
tasks eagerly. This is both suboptimal and actually not aligned with the
generated build scripts that use Kotlin DSL, which configures tasks
lazily.

This commit updates `GroovyDslGradleBuildWriter` to ensure tasks are
configured lazily.

See gh-1292

Author: vpavic

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/build/gradle/GradleProjectGenerationConfigurationTests.java

@@ -129,7 +129,7 @@ void buildDotGradleIsContributedWhenGeneratingGradleProject() {
 				"    testImplementation 'org.springframework.boot:spring-boot-starter-test'",
 				"}",
 				"",
-				"test {",
+				"tasks.named('test') {",
 				"    useJUnitPlatform()",
 				"}"); // @formatter:on
 	}
@@ -150,7 +150,8 @@ void junitPlatformIsConfiguredWithCompatibleVersion() {
 		description.setPlatformVersion(Version.parse("2.2.4.RELEASE"));
 		description.setLanguage(new JavaLanguage());
 		ProjectStructure project = this.projectTester.generate(description);
-		assertThat(project).textFile("build.gradle").lines().containsSequence("test {", "    useJUnitPlatform()", "}");
+		assertThat(project).textFile("build.gradle").lines().containsSequence("tasks.named('test') {",
+				"    useJUnitPlatform()", "}");
 	}
 
 	@Test

initializr-generator-spring/src/test/resources/project/gradle/annotation-processor-dependency-build.gradle.gen

@@ -25,6 +25,6 @@ dependencies {
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'
 }
 
-test {
+tasks.named('test') {
 	useJUnitPlatform()
 }

initializr-generator-spring/src/test/resources/project/gradle/bom-ordering-build.gradle.gen

@@ -25,6 +25,6 @@ dependencyManagement {
 	}
 }
 
-test {
+tasks.named('test') {
 	useJUnitPlatform()
 }

initializr-generator-spring/src/test/resources/project/gradle/bom-property-build.gradle.gen

@@ -27,6 +27,6 @@ dependencyManagement {
 	}
 }
 
-test {
+tasks.named('test') {
 	useJUnitPlatform()
 }

initializr-generator-spring/src/test/resources/project/gradle/compile-only-dependency-build.gradle.gen

@@ -19,6 +19,6 @@ dependencies {
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'
 }
 
-test {
+tasks.named('test') {
 	useJUnitPlatform()
 }

initializr-generator-spring/src/test/resources/project/gradle/kotlin-java11-build.gradle.gen

@@ -29,6 +29,6 @@ tasks.withType(KotlinCompile) {
 	}
 }
 
-test {
+tasks.named('test') {
 	useJUnitPlatform()
 }

initializr-generator-spring/src/test/resources/project/gradle/repositories-build.gradle.gen

@@ -20,6 +20,6 @@ dependencies {
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'
 }
 
-test {
+tasks.named('test') {
 	useJUnitPlatform()
 }

initializr-generator-spring/src/test/resources/project/gradle/repositories-milestone-build.gradle.gen

@@ -18,6 +18,6 @@ dependencies {
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'
 }
 
-test {
+tasks.named('test') {
 	useJUnitPlatform()
 }

initializr-generator-spring/src/test/resources/project/gradle/version-override-build.gradle.gen

@@ -22,6 +22,6 @@ dependencies {
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'
 }
 
-test {
+tasks.named('test') {
 	useJUnitPlatform()
 }

initializr-generator-spring/src/test/resources/project/groovy/standard/build.gradle.gen

@@ -18,6 +18,6 @@ dependencies {
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'
 }
 
-test {
+tasks.named('test') {
 	useJUnitPlatform()
 }