Generate field for const-val with same visibility as desciptor

Also add test checking that constant static final fields generated for them

compiler/testData/codegen/boxWithStdlib/fullJdk/constFlags.kt

@@ -0,0 +1,47 @@
+@file:JvmName("XYZ")
+import java.lang.reflect.Modifier
+
+private const val privateConst: Int = 1
+public const val publicConst: Int = 3
+
+public object A {
+    private const val privateConst: Int = 1
+    protected const val protectedConst: Int = 2
+    public const val publicConst: Int = 3
+}
+
+public class B {
+    companion object {
+        private const val privateConst: Int = 1
+        protected const val protectedConst: Int = 2
+        public const val publicConst: Int = 3
+    }
+}
+
+fun check(clazz: Class<*>, expectProtected: Boolean = true) {
+    val fields = clazz.declaredFields.filter { it.name.contains("Const") }
+
+    assert(fields.all { Modifier.isStatic(it.modifiers) }) { "`$clazz` contains non-static fields" }
+
+    assert(Modifier.isPrivate(fields.single { it.name.contains("private") }.modifiers)) {
+        "`$clazz`.privateConst is not private"
+    }
+
+    assert(Modifier.isPublic(fields.single { it.name.contains("public") }.modifiers)) {
+        "`$clazz`.publicConst is not public"
+    }
+
+    if (expectProtected) {
+        assert(Modifier.isProtected(fields.single { it.name.contains("protected") }.modifiers)) {
+            "`$clazz`.protectedConst is not protected"
+        }
+    }
+}
+
+fun box(): String {
+    check(A::class.java)
+    check(B::class.java)
+    check(Class.forName("XYZ"), false)
+
+    return "OK"
+}