Cleanup cassandra smoke test removal

See gh-19588

spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-data-cassandra/build.gradle

@@ -1,40 +0,0 @@
-buildscript {
-	dependencies {
-		classpath "org.springframework:spring-core:5.2.2.RELEASE"
-	}
-}
-
-plugins {
-	id "java"
-	id "org.springframework.boot.conventions"
-}
-
-description = "Spring Boot Data Cassandra smoke test"
-
-dependencies {
-	implementation(project(":spring-boot-project:spring-boot-starters:spring-boot-starter-data-cassandra"))
-
-	testImplementation(project(":spring-boot-project:spring-boot-starters:spring-boot-starter-test"))
-	testImplementation("org.cassandraunit:cassandra-unit-spring:3.5.0.1") {
-		exclude group: "org.slf4j", module: "jcl-over-slf4j"
-	}
-}
-
-test {
-	jvmArgumentProviders.add new CassandraPortsProvider()
-	enabled = !JavaVersion.current().java9Compatible
-}
-
-class CassandraPortsProvider implements CommandLineArgumentProvider {
-
-	@Override
-	Iterable<String> asArguments() {
-		def ports = org.springframework.util.SocketUtils.findAvailableTcpPorts(2)
-		return [
-				"-Dspring.data.cassandra.port=${ports[0]}",
-				"-Dcassandra.native_transport_port=${ports[0]}",
-				"-Dcassandra.port.storage=${ports[1]}"
-		]
-	}
-
-}