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

native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/NativeCodegenBoxTestGenerated.java

@@ -8041,6 +8041,12 @@ public class NativeCodegenBoxTestGenerated extends AbstractNativeCodegenBoxTest
                 runTest("compiler/testData/codegen/box/coroutines/kt49168.kt");
             }
 
+            @Test
+            @TestMetadata("kt49317.kt")
+            public void testKt49317() throws Exception {
+                runTest("compiler/testData/codegen/box/coroutines/kt49317.kt");
+            }
+
             @Test
             @TestMetadata("kt51530.kt")
             public void testKt51530() throws Exception {