Implement correct is check for SuspendFunction

Let callable references implement SuspendFunction
Do not generate CHECKCAST SuspendFunction when LV is 1.2

 #KT-25825: Fixed

compiler/testData/codegen/box/coroutines/featureIntersection/suspendFunction12.kt

@@ -0,0 +1,19 @@
+// IGNORE_BACKEND: JS_IR, JS
+// IGNORE_BACKEND: JVM_IR
+// WITH_RUNTIME
+// WITH_COROUTINES
+// LANGUAGE_VERSION: 1.2
+
+import helpers.*
+import kotlin.coroutines.*
+
+val lambda1 = { x: Any -> } as (Any) -> Unit
+val suspendLambda0: suspend () -> Unit = {}
+
+fun box(): String {
+    assert(lambda1 is SuspendFunction0<*>) { "Failed: lambda1 !is SuspendFunction0<*>" }
+    assert(suspendLambda0 is Function1<*, *>) { "Failed: suspendLambda0 is Function1<*, *>" }
+    assert(suspendLambda0 is SuspendFunction0<*>) { "Failed: suspendLambda0 is SuspendFunction0<*>" }
+
+    return "OK"
+}

compiler/testData/codegen/box/coroutines/featureIntersection/suspendFunctionIsAs.kt

@@ -0,0 +1,61 @@
+// IGNORE_BACKEND: JS_IR, JS
+// IGNORE_BACKEND: JVM_IR
+// WITH_RUNTIME
+// WITH_COROUTINES
+// LANGUAGE_VERSION: 1.3
+
+import helpers.*
+import kotlin.coroutines.*
+
+fun fn1(x: Any) {}
+suspend fun suspendFn0() {}
+
+val lambda1 = { x: Any -> } as (Any) -> Unit
+val suspendLambda0: suspend () -> Unit = {}
+
+fun Any.extFun(a: Any) {}
+suspend fun Any.suspendExtFun() {}
+
+class A {
+    fun foo(a: Any) {}
+    suspend fun suspendFoo() {}
+}
+
+fun box(): String {
+    val f1 = ::fn1 as Any
+    val sf0 = ::suspendFn0 as Any
+
+    val ef = Any::extFun as Any
+    val sef = Any::suspendExtFun as Any
+
+    val afoo = A::foo
+    val safoo = A::suspendFoo
+
+    fun local1(x: Any) {}
+    suspend fun suspendLocal0() {}
+
+    val localFun1 = ::local1 as Any
+    val suspendLocalFun0 = ::suspendLocal0 as Any
+
+    assert(f1 !is SuspendFunction0<*>) { "Failed: f1 !is SuspendFunction0<*>" }
+    assert(sf0 is SuspendFunction0<*>) { "Failed: f1 is SuspendFunction0<*>" }
+    assert(sf0 is Function1<*, *>) { "Failed: suspendF0 is Function1<*, *>" }
+
+    assert(lambda1 !is SuspendFunction0<*>) { "Failed: lambda1 !is SuspendFunction0<*>" }
+    assert(suspendLambda0 is Function1<*, *>) { "Failed: suspendLambda0 is Function1<*, *>" }
+    assert(suspendLambda0 is SuspendFunction0<*>) { "Failed: suspendLambda0 is SuspendFunction0<*>" }
+
+    assert(localFun1 !is SuspendFunction0<*>) { "Failed: localFun1 !is SuspendFunction0<*, *>" }
+    assert(suspendLocalFun0 is Function1<*, *>) { "Failed: suspendLocalFun0 is Function1<*, *>" }
+    assert(suspendLocalFun0 is SuspendFunction0<*>) { "Failed: suspendLocalFun0 is SuspendFunction0<*>" }
+
+    assert(ef !is SuspendFunction1<*, *>) { "Failed: ef !is SuspendFunction1<*, *>" }
+    assert(sef is SuspendFunction1<*, *>) { "Failed: sef is SuspendFunction1<*, *>" }
+    assert(sef is Function2<*, *, *>) { "Failed: sef is Function2<*, *, *>" }
+
+    assert(afoo !is SuspendFunction1<*, *>) { "afoo !is SuspendFunction1<*, *>" }
+    assert(safoo is Function2<*, *, *>) { "safoo is Function2<*, *, *>" }
+    assert(safoo is SuspendFunction1<*, *>) { "asfoo is SuspendFunction1<*, *>" }
+
+    return "OK"
+}