Update build in preparation for Gradle 2.0

As of Gradle 1.8, ‘testReport true’ is deprecated. Thus in order to
generate TestNG reports alongside JUnit reports with Gradle 2.0 and
beyond, we are now using:

  getReports().getHtml().setEnabled(true)

build.gradle

@@ -816,7 +816,7 @@ project("spring-test") {
 		// "TestCase" classes are run by other test classes, not the build.
 		exclude "**/*TestCase.class"
 		// Generate TestNG reports alongside JUnit reports.
-		testReport true
+		getReports().getHtml().setEnabled(true)
 	}
 
 	test {