Native: don't expect that startCoroutineUninterceptedOrReturn receiver is FunctionN+1

Previous implementation of startCoroutineUninterceptedOrReturn expected
that the receiver (i.e. the suspend function object to start) of type
SuspendFunctionN (i.e. suspend function type with arity = N) is also an
instance of FunctionN+1 (i.e. regular function type with arity = N + 1)
with proper convention.

While compiler tries to achieve that (for better compatibility with
Kotlin/JVM, by generating additional supertypes and methods for classes
implementing suspend function types), this doesn't work e.g. for
implementations defined in Swift.

Fix this by adding fallbacks for cases when the receiver is not
a FunctionN+1, while keeping the fastpath for default FunctionN+1
cases.

^KT-51043 Fixed

kotlin-native/runtime/src/main/kotlin/kotlin/coroutines/intrinsics/IntrinsicsNative.kt

@@ -25,7 +25,25 @@ import kotlin.native.internal.*
 @kotlin.internal.InlineOnly
 public actual inline fun <T> (suspend () -> T).startCoroutineUninterceptedOrReturn(
         completion: Continuation<T>
-): Any? = (this as Function1<Continuation<T>, Any?>).invoke(completion)
+): Any? {
+    val function = this as? Function1<Continuation<T>, Any?>
+    return if (function != null)
+        function.invoke(completion)
+    else
+        startCoroutineUninterceptedOrReturnFallback(this, completion)
+}
+
+@Suppress("UNCHECKED_CAST")
+@PublishedApi
+internal fun <T> startCoroutineUninterceptedOrReturnFallback(
+        function: suspend () -> T,
+        completion: Continuation<T>
+): Any? {
+    // Unlike `function`, `wrapper` class is generated and lowered entirely by Kotlin compiler,
+    // so the cast below will succeed.
+    val wrapper: suspend () -> T = { function() }
+    return (wrapper as Function1<Continuation<T>, Any?>).invoke(completion)
+}
 
 /**
  * Starts an unintercepted coroutine with receiver type [R] and result type [T] and executes it until its first suspension.
@@ -44,7 +62,26 @@ public actual inline fun <T> (suspend () -> T).startCoroutineUninterceptedOrRetu
 public actual inline fun <R, T> (suspend R.() -> T).startCoroutineUninterceptedOrReturn(
         receiver: R,
         completion: Continuation<T>
-): Any? = (this as Function2<R, Continuation<T>, Any?>).invoke(receiver, completion)
+): Any? {
+    val function = this as? Function2<R, Continuation<T>, Any?>
+    return if (function != null)
+        function.invoke(receiver, completion)
+    else
+        startCoroutineUninterceptedOrReturnFallback(this, receiver, completion)
+}
+
+@Suppress("UNCHECKED_CAST")
+@PublishedApi
+internal fun <R, T> startCoroutineUninterceptedOrReturnFallback(
+        function: suspend R.() -> T,
+        receiver: R,
+        completion: Continuation<T>
+): Any? {
+    // Unlike `function`, `wrapper` class is generated and lowered entirely by Kotlin compiler,
+    // so the cast below will succeed.
+    val wrapper: suspend R.() -> T = { this.function() }
+    return (wrapper as Function2<R, Continuation<T>, Any?>).invoke(receiver, completion)
+}
 
 @Suppress("UNCHECKED_CAST")
 @kotlin.internal.InlineOnly
@@ -52,7 +89,26 @@ internal actual inline fun <R, P, T> (suspend R.(P) -> T).startCoroutineUninterc
         receiver: R,
         param: P,
         completion: Continuation<T>
-): Any? = (this as Function3<R, P, Continuation<T>, Any?>).invoke(receiver, param, completion)
+): Any? {
+    val function = this as? Function3<R, P, Continuation<T>, Any?>
+    return if (function != null)
+        function.invoke(receiver, param, completion)
+    else
+        startCoroutineUninterceptedOrReturnFallback(this, receiver, param, completion)
+}
+
+@Suppress("UNCHECKED_CAST")
+internal fun <R, P, T> startCoroutineUninterceptedOrReturnFallback(
+        function: suspend R.(P) -> T,
+        receiver: R,
+        param: P,
+        completion: Continuation<T>
+): Any? {
+    // Unlike `function`, `wrapper` class is generated and lowered entirely by Kotlin compiler,
+    // so the cast below will succeed.
+    val wrapper: suspend R.(P) -> T = { this.function(it) }
+    return (wrapper as Function3<R, P, Continuation<T>, Any?>).invoke(receiver, param, completion)
+}
 
 private object CoroutineSuspendedMarker