Ignore open modifier on top-level suspend function when generating light classes

#KT-21642: Fixed

compiler/backend/src/org/jetbrains/kotlin/codegen/FunctionCodegen.java

@@ -242,6 +242,7 @@ public class FunctionCodegen {
                 functionDescriptor.isSuspend() &&
                 functionDescriptor.getModality() != Modality.ABSTRACT && isOverridable(functionDescriptor) &&
                 !isInterface(functionDescriptor.getContainingDeclaration()) &&
+                !(functionDescriptor.getContainingDeclaration() instanceof PackageFragmentDescriptor) &&
                 origin.getOriginKind() != JvmDeclarationOriginKind.CLASS_MEMBER_DELEGATION_TO_DEFAULT_IMPL;
 
         if (isOpenSuspendInClass) {

idea/testData/highlighter/TopLevelOpenSuspendFun.kt

@@ -0,0 +1 @@
+<error descr="[WRONG_MODIFIER_TARGET] Modifier 'open' is not applicable to 'top level function'"><info descr="null">open</info></error> <warning descr="[EXPERIMENTAL_FEATURE_WARNING] The feature \"coroutines\" is experimental (see: https://kotlinlang.org/docs/diagnostics/experimental-coroutines)"><info descr="null">suspend</info></warning> fun <info descr="null">f</info>() {}

idea/tests/org/jetbrains/kotlin/idea/highlighter/HighlightingTestGenerated.java

@@ -121,6 +121,12 @@ public class HighlightingTestGenerated extends AbstractHighlightingTest {
         doTest(fileName);
     }
 
+    @TestMetadata("TopLevelOpenSuspendFun.kt")
+    public void testTopLevelOpenSuspendFun() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/highlighter/TopLevelOpenSuspendFun.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("TypeAlias.kt")
     public void testTypeAlias() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/highlighter/TypeAlias.kt");