JVM IR: Do not create accessors for enum entry constructors

compiler/testData/codegen/bytecodeText/enum/constructorAccessors.kt

@@ -0,0 +1,15 @@
+enum class E(private val value: Int) {
+    A(0) {
+        override fun f() {}
+    },
+    B(1) {
+        override fun f() {}
+    };
+
+    abstract fun f()
+}
+
+// The JVM BE creates an accessor for the constructor of `E`, but not for the constructors of the enum entry classes E$A and E$B.
+// 1 public synthetic <init>\(Ljava/lang/String;IILkotlin/jvm/internal/DefaultConstructorMarker;\)V
+// 2 INVOKESPECIAL E.<init> \(Ljava/lang/String;IILkotlin/jvm/internal/DefaultConstructorMarker;\)V
+// 3 kotlin/jvm/internal/DefaultConstructorMarker;\)