Remove some legacy codegen tests, move some to generated

compiler/testData/codegen/enum/name.kt

@@ -1,6 +0,0 @@
-enum class State {
-  O,
-  K
-}
-
-fun box() = "${State.O.name}${State.K.name}"

compiler/testData/codegen/enum/openMethod.kt

@@ -1,10 +0,0 @@
-fun box() = IssueState.DEFAULT.ToString() + IssueState.FIXED.ToString()
-
-enum class IssueState {
-   DEFAULT,
-   FIXED {
-       override fun ToString() = "K"
-   };
-
-   open fun ToString() : String = "O"
-}

compiler/testData/codegen/enum/simple.kt

@@ -1,12 +0,0 @@
-enum class Season {
-    WINTER,
-    SPRING,
-    SUMMER,
-    AUTUMN
-}
-
-fun foo(): Season = Season.SPRING
-
-fun box() =
-    if (foo() == Season.SPRING) "OK"
-    else "fail"