Support local suspend functions

Treat them like lambdas. This means:
1) Like local suspend lambdas, which become "non-suspend" after creating
jvmSuspendView, they do this as well
2) They both are generated with the same codegen.
3) They are treated differently only on front-end side.
 #KT-20364: Fixed

compiler/frontend/src/org/jetbrains/kotlin/resolve/ModifiersChecker.kt

@@ -72,7 +72,7 @@ object ModifierCheckerCore {
         INLINE_KEYWORD to EnumSet.of(FUNCTION, PROPERTY, PROPERTY_GETTER, PROPERTY_SETTER, CLASS_ONLY),
         NOINLINE_KEYWORD to EnumSet.of(VALUE_PARAMETER),
         TAILREC_KEYWORD to EnumSet.of(FUNCTION),
-        SUSPEND_KEYWORD to EnumSet.of(MEMBER_FUNCTION, TOP_LEVEL_FUNCTION),
+        SUSPEND_KEYWORD to EnumSet.of(MEMBER_FUNCTION, TOP_LEVEL_FUNCTION, LOCAL_FUNCTION),
         EXTERNAL_KEYWORD to EnumSet.of(FUNCTION, PROPERTY, PROPERTY_GETTER, PROPERTY_SETTER, CLASS),
         ANNOTATION_KEYWORD to EnumSet.of(ANNOTATION_CLASS),
         CROSSINLINE_KEYWORD to EnumSet.of(VALUE_PARAMETER),