Don't generate private members in interface

compiler/testData/codegen/bytecodeText/interfaces/noPrivateMemberInJavaInterface.kt

@@ -0,0 +1,17 @@
+interface A {
+
+    private val prop: String
+        get() = "1"
+
+    private fun foo() {
+
+    }
+
+    private fun defaultFun(p: String = "OK") {
+
+    }
+}
+
+// 1 foo
+// 1 getProp
+// 1 defaultFun\$