properly read vararg signature from java code

KT-1694 Java vararg override, Why is it intuitive interface?

#KT-1694 Fixed

compiler/testData/diagnostics/tests/j+k/OverrideVararg.jet

@@ -0,0 +1,12 @@
+// FILE: Aaa.java
+// http://youtrack.jetbrains.com/issue/KT-1694
+
+public abstract class Aaa {
+    public abstract void foo(String... args);
+}
+
+// FILE: bbb.kt
+
+class Bbb() : Aaa() {
+    override fun foo(vararg args: String?) = #()
+}