An implementation of KT-7753: now enum constructors cannot be called explicitly.

Several tests are provided.
 #KT-7753 Fixed.

compiler/testData/diagnostics/tests/enum/OldSyntaxConstructorCall.kt

@@ -0,0 +1,10 @@
+// KT-7753: attempt to call enum constructor explicitly
+enum class A(val c: Int) {
+    // No errors at both places, but warnings about deprecated
+    ONE: <!ENUM_ENTRY_USES_DEPRECATED_SUPER_CONSTRUCTOR!>A(1)<!>,
+    TWO: <!ENUM_ENTRY_USES_DEPRECATED_SUPER_CONSTRUCTOR!>A(2)<!>;
+    
+    fun getA(): A {
+        return ONE
+    }
+}