Move some tests from boxWithStdlib/ to box/

Move those tests which do not require neither stdlib nor reflect

compiler/testData/codegen/box/when/enumOptimization/nonConstantEnum.kt

@@ -0,0 +1,16 @@
+enum class Season {
+    WINTER,
+    SPRING,
+    SUMMER,
+    AUTUMN
+}
+
+fun foo(): Season = Season.SPRING
+fun bar(): Season = Season.SPRING
+
+fun box() : String {
+    when (foo()) {
+        bar() -> return "OK"
+        else -> return "fail"
+    }
+}

compiler/testData/codegen/box/when/enumOptimization/nullableEnum.kt

@@ -0,0 +1,14 @@
+enum class E {
+    A,
+    B
+}
+
+fun test(e: E?) = when (e) {
+    E.A -> "Fail A"
+    null -> "OK"
+    E.B -> "Fail B"
+}
+
+fun box(): String {
+    return test(null)
+}

compiler/testData/codegen/box/when/exhaustiveBreakContinue.kt

@@ -0,0 +1,14 @@
+enum class Color { RED, GREEN, BLUE }
+
+fun foo(arr: Array<Color>): Color {
+    loop@ for (color in arr) {
+        when (color) {
+            Color.RED -> return color
+            Color.GREEN -> break@loop
+            Color.BLUE -> if (arr.size == 1) return color else continue@loop
+        }
+    }
+    return Color.GREEN
+}
+
+fun box() = if (foo(arrayOf(Color.BLUE, Color.GREEN)) == Color.GREEN) "OK" else "FAIL"