Move blackBoxFile() testData to box/ directory

Delete all test methods (and empty test classes), since they'll be
auto-generated

compiler/testData/codegen/box/controlStructures/kt2416.kt

@@ -0,0 +1,15 @@
+fun box(): String {
+    9 in 0..9
+    val intRange = 0..9
+    9 in intRange
+    val charRange = '0'..'9'
+    '9' in charRange
+    val byteRange = 0.toByte()..9.toByte()
+    9.toByte() in byteRange
+    val longRange = 0.toLong()..9.toLong()
+    9.toLong() in longRange
+    val shortRange = 0.toShort()..9.toShort()
+    9.toShort() in shortRange
+
+    return "OK"
+}