Fix #7410: add test

Author: liufengyun

tests/run/i7410/Enum_1.scala

@@ -0,0 +1,3 @@
+enum E {
+  case A, B, C
+}

tests/run/i7410/Test_2.scala

@@ -0,0 +1,6 @@
+object Test {
+  def main(args: Array[String]): Unit = {
+    val a = E.A
+    println(a)
+  }
+}