Fix #7287: add test

Author: liufengyun

tests/run/i7287/Enum_1.scala

@@ -0,0 +1,5 @@
+enum Color derives Eql {
+  case Unknown
+  case Blue(v: Int)
+  case Red(v: Int)
+}

tests/run/i7287/Test_2.scala

@@ -0,0 +1,6 @@
+object Test {
+  def main(args: Array[String]): Unit = {
+    val testData = Seq(("blah", Color.Unknown), ("red", Color.Red(10)))
+    println(testData)
+  }
+}