fix for KT-2711 wrong check on descriptor being integral range

method added to JetStandardLibrary to get all integral range descriptors
#KT-2711 fixed

compiler/testData/codegen/regressions/kt2711.kt

@@ -0,0 +1,14 @@
+class IntRange {
+    fun contains(a: Int) = (1..2).contains(a)
+}
+
+class C() {
+    fun rangeTo(i: Int) = IntRange()
+}
+
+
+fun main(args: Array<String>) {
+    if (2 in C()..2) {
+        System.out?.println(2)
+    }
+}