Support const-bound counter loop generation for 'downTo'

compiler/testData/codegen/box/ranges/forWithPossibleOverflow/forInDownToCharMinValue.kt

@@ -0,0 +1,15 @@
+// WITH_RUNTIME
+
+const val M = 0.toChar()
+
+fun box(): String {
+    var count = 0
+    for (i in M downTo M) {
+        ++count
+        if (count > 1) {
+            throw AssertionError("Loop should be executed once")
+        }
+    }
+    if (count != 1) throw AssertionError("Should be executed once")
+    return "OK"
+}

compiler/testData/codegen/box/ranges/forWithPossibleOverflow/forInDownToIntMinValue.kt

@@ -0,0 +1,15 @@
+// WITH_RUNTIME
+
+const val M = Int.MIN_VALUE
+
+fun box(): String {
+    var count = 0
+    for (i in M downTo M) {
+        ++count
+        if (count > 1) {
+            throw AssertionError("Loop should be executed once")
+        }
+    }
+    if (count != 1) throw AssertionError("Should be executed once")
+    return "OK"
+}

compiler/testData/codegen/box/ranges/forWithPossibleOverflow/forInDownToLongMinValue.kt

@@ -0,0 +1,15 @@
+// WITH_RUNTIME
+
+const val M = Long.MIN_VALUE
+
+fun box(): String {
+    var count = 0
+    for (i in M downTo M) {
+        ++count
+        if (count > 1) {
+            throw AssertionError("Loop should be executed once")
+        }
+    }
+    if (count != 1) throw AssertionError("Should be executed once")
+    return "OK"
+}