Use module path instead of class path for stdlib on Java 9

Also report the "named does not read unnamed" error, which was not
possible previously because we wouldn't be able to read anything from
kotlin-stdlib (because it was added to the unnamed module by default)

compiler/tests-common/org/jetbrains/kotlin/codegen/forTestCompile/ForTestCompileRuntime.java

@@ -33,7 +33,7 @@ public class ForTestCompileRuntime {
 
     @NotNull
     public static File runtimeJarForTests() {
-        return assertExists(new File("dist/kotlinc/lib/kotlin-runtime.jar"));
+        return assertExists(new File("dist/kotlinc/lib/kotlin-stdlib.jar"));
     }
 
     @NotNull