Build default jvm core libraries artifacts as modular

#KT-21266

libraries/kotlin.test/jvm/build.gradle

@@ -23,9 +23,10 @@ dependencies {
 archivesBaseName = 'kotlin-test'
 
 jar {
-    manifestAttributes(manifest, project, 'Test' /*true*/)
-    // TODO: enable as soon as this doesn't cause D8/DX to crash
-    // from sourceSets.java9.output
+    manifestAttributes(manifest, project, 'Test', true)
+    if (includeJava9) {
+        from sourceSets.java9.output
+    }
 }
 
 task modularJar(type: Jar) {
@@ -34,9 +35,6 @@ task modularJar(type: Jar) {
     classifier = 'modular'
 
     from zipTree(jar.outputs.files.singleFile)
-    if (includeJava9) {
-        from sourceSets.java9.output
-    }
 }
 
 artifacts {