Assemble iajc Ant task classpath w/ folders that exist

Prior to this commit, the [ant:iajc] tasks logged numerous warnings
regarding incorrect classpath entries. The reason is that the classpath
was constructed with paths that do not physically exist in the file
system (e.g., for projects that do not have test classes or test
folders (yet)).

This commit picks up where ef75bd8 left off and addresses this issue by
assembling the runtime classpath passed to the iajc task with folders
and JARs that actually exist in the filesystem.

spring-aspects/aspects.gradle

@@ -25,6 +25,9 @@ compileJava  {
 	ext.targetCompatibility = project(":spring-core").compileJava.targetCompatibility
 
 	doLast{
+		// Assemble runtime classpath from folders and JARs that actually exist
+		def runtimeClasspath = project.files(sourceSets.main.runtimeClasspath.files.findAll({ it.exists() }))
+
 		ant.taskdef(resource: "org/aspectj/tools/ant/taskdefs/aspectjTaskdefs.properties",
 				classpath: configurations.ajc.asPath)
 
@@ -34,7 +37,7 @@ compileJava  {
 				aspectPath: configurations.aspects.asPath,
 				inpath: configurations.ajInpath.asPath,
 				sourceRootCopyFilter: "**/*.java,**/*.aj",
-				classpath: (sourceSets.main.runtimeClasspath + configurations.rt).asPath) {
+				classpath: (runtimeClasspath + configurations.rt).asPath) {
 			sourceroots {
 				sourceSets.main.java.srcDirs.each {
 					pathelement(location:it.absolutePath)
@@ -56,9 +59,11 @@ compileTestJava  {
 
 	ext.sourceCompatibility = project(":spring-core").compileTestJava.sourceCompatibility
 	ext.targetCompatibility = project(":spring-core").compileTestJava.targetCompatibility
-	ext.pathSeparator = System.getProperty('path.separator')
 
 	doLast{
+		// Assemble runtime classpath from folders and JARs that actually exist
+		def runtimeClasspath = project.files(sourceSets.test.runtimeClasspath.files.findAll({ it.exists() }))
+
 		ant.taskdef(resource: "org/aspectj/tools/ant/taskdefs/aspectjTaskdefs.properties",
 				classpath: configurations.ajc.asPath)
 
@@ -67,7 +72,7 @@ compileTestJava  {
 				destDir: outputDir.absolutePath,
 				aspectPath: jar.archivePath,
 				inpath: configurations.ajInpath.asPath,
-				classpath: sourceSets.test.runtimeClasspath.asPath + pathSeparator + jar.archivePath + pathSeparator + configurations.rt.asPath) {
+				classpath: (runtimeClasspath + project.files(jar.archivePath) + configurations.rt).asPath) {
 			sourceroots {
 				sourceSets.test.java.srcDirs.each {
 					pathelement(location:it.absolutePath)