Fix Eclipse support in Gradle build

The upgrade to Gradle 4.0 broke the custom Eclipse support in the
Spring Framework build.

This commit includes the following changes which re-enable support for
Eclipse in the build.

- Switched to ProjectDependency(String) constructor

- Updated regular expression that matches against project output
  dependencies to include more than one subdirectory between "build"
  and "main"|"test".

Issue: SPR-15862

gradle/ide.gradle

@@ -13,7 +13,7 @@ eclipse.jdt {
 // Replace classpath entries with project dependencies (GRADLE-1116)
 // http://issues.gradle.org/browse/GRADLE-1116
 eclipse.classpath.file.whenMerged { classpath ->
-	def regexp = /.*?\/([^\/]+)\/build\/[^\/]+\/(?:main|test)/ // only match those that end in main or test (avoids removing necessary entries like build/classes/jaxb)
+	def regexp = /.*?\/([^\/]+)\/build\/([^\/]+\/)+(?:main|test)/ // only match those that end in main or test (avoids removing necessary entries like build/classes/jaxb)
 	def projectOutputDependencies = classpath.entries.findAll { entry -> entry.path =~ regexp }
 	projectOutputDependencies.each { entry ->
 		def matcher = (entry.path =~ regexp)
@@ -21,7 +21,7 @@ eclipse.classpath.file.whenMerged { classpath ->
 			def projectName = matcher[0][1]
 			def path = "/${projectName}"
 			if(!classpath.entries.find { e -> e instanceof ProjectDependency && e.path == path }) {
-				def dependency = new ProjectDependency(path, project(":${projectName}").path)
+				def dependency = new ProjectDependency(path)
 				dependency.exported = true
 				classpath.entries.add(dependency)
 			}