Optimize checkTestConfigs task for UP_TO_DATE

We really don't need to parse `inputs.files` for wrong XSD configuration.
This is already a responsibility of the task.
There is just enough to track changes in the XML configs and if they
happened only after that treat the task as out of date and parse configs
for wrong XSD configuration

build.gradle

@@ -192,22 +192,22 @@ subprojects { subproject ->
 	[compileJava, compileTestJava]*.options*.compilerArgs = [xLintArg]
 
 	task checkTestConfigs {
-		def configFiles = []
-		sourceSets.test.java.srcDirs.each {
-			fileTree(it).include('**/*.xml').exclude('**/log4j2-test.xml').each { configFile ->
-				def configXml = new XmlParser(false, false).parse(configFile)
-
-				if (configXml.@'xsi:schemaLocation' ==~ /.*spring-[a-z-]*\d\.\d\.xsd.*/) {
-					configFiles << configFile
-				}
-			}
-		}
-		inputs.files(configFiles)
+		inputs.files(
+				sourceSets.test.java.srcDirs.collect {
+							fileTree(it)
+								.include('**/*.xml')
+								.exclude('**/log4j2-test.xml')
+				})
 		outputs.dir('build')
 		doLast {
-			if (!inputs.files.empty) {
+			def wrongConfigs = inputs.files.filter {
+				new XmlParser(false, false)
+						.parse(it)
+						.@'xsi:schemaLocation' ==~ /.*spring-[a-z-]*\d\.\d\.xsd.*/
+			}
+			if (!wrongConfigs.empty) {
 				throw new InvalidUserDataException('Hardcoded XSD version in the config files:\n' +
-						inputs.files.collect {relativePath(it) }.join('\n') +
+						wrongConfigs.collect { relativePath(it) }.join('\n') +
 						'\nPlease, use versionless schemaLocations for Spring XSDs to avoid issues with builds ' +
 						'on different versions of dependencies.')
 			}