KT-7918 J2K: don't generate jvmOverloads on private declarations

#KT-7918 Fixed

j2k/testData/fileOrElement/constructors/privateConstructors.kt

@@ -1,4 +1,4 @@
-class C jvmOverloads private constructor(arg1: Int, arg2: Int, arg3: Int = 0) {
+class C private constructor(arg1: Int, arg2: Int, arg3: Int = 0) {
 
     public constructor(arg1: Int) : this(arg1, 0, 0) {
     }

j2k/testData/fileOrElement/overloads/Private.java

@@ -0,0 +1,10 @@
+class A {
+    private int bar(String s) {
+        System.out.println("s = " + s);
+        return 0;
+    }
+
+    private int bar() {
+        return bar(null);
+    }
+}

j2k/testData/fileOrElement/overloads/Private.kt

@@ -0,0 +1,6 @@
+class A {
+    private fun bar(s: String? = null): Int {
+        println("s = " + s!!)
+        return 0
+    }
+}