Safely check for suspend function parent

The issue here is that the function can be in unlowered file, and
thus its parent package fragment and not class.

 #KT-49317 Fixed

compiler/testData/codegen/box/coroutines/kt49317.kt

@@ -0,0 +1,26 @@
+// WITH_STDLIB
+
+// FILE: 2.kt
+package other
+import builders.*
+import kotlin.coroutines.*
+
+fun test() {
+    suspend {
+        foo {  }
+    }.startCoroutine(Continuation(EmptyCoroutineContext) {
+        it.getOrThrow()
+    })
+}
+
+fun box(): String {
+    test()
+    return "OK"
+}
+
+// FILE: 1.kt
+package builders
+
+suspend fun foo(
+    a: suspend () -> Unit = {}
+) {}