Load Java overrides of Kotlin suspend functions as suspend, too

There's still some blind spots:
- Covariant overrides in Java (KT-25036)
- Current implementation assumes that when language version is 1.3 every suspend function
reference only release-coroutines-package Continuation
(we need to check if it's a correct statement)

 #KT-24848 Fixed
 #KT-25036 Open

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

@@ -0,0 +1,49 @@
+// TARGET_BACKEND: JVM
+// WITH_RUNTIME
+// WITH_COROUTINES
+// COMMON_COROUTINES_TEST
+
+// FILE: I.kt
+
+interface I {
+    suspend fun foo(x: Int): String
+    suspend fun bar(x: Int): String
+}
+
+// FILE: JavaClass.java
+
+public class JavaClass implements I {
+    @Override
+    public String foo(int x, COROUTINES_PACKAGE.Continuation<? super String> continuation) {
+        return "O";
+    }
+
+    @Override
+    public Object bar(int x, COROUTINES_PACKAGE.Continuation<? super String> continuation) {
+        return foo(x, continuation);
+    }
+}
+
+// FILE: main.kt
+import helpers.*
+import COROUTINES_PACKAGE.*
+import COROUTINES_PACKAGE.intrinsics.*
+
+class K : JavaClass() {
+    override suspend fun foo(x: Int): String = super.foo(x) + suspendCoroutine { it.resume("K") }
+}
+
+fun builder(c: suspend () -> Unit) {
+    c.startCoroutine(EmptyContinuation)
+}
+
+fun box(): String {
+    var result = "fail"
+
+    builder {
+        // Changing the call to 'K().bar(1)' doesn't work because of KT-25036
+        result = K().foo(1)
+    }
+
+    return result
+}

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

@@ -0,0 +1,39 @@
+// TARGET_BACKEND: JVM
+// WITH_RUNTIME
+// WITH_COROUTINES
+// COMMON_COROUTINES_TEST
+
+// FILE: I.kt
+
+interface I {
+    suspend fun foo(x: Int): String
+}
+
+// FILE: JavaClass.java
+
+public class JavaClass implements I {
+    @Override
+    public Object foo(int x, COROUTINES_PACKAGE.Continuation<? super String> continuation) {
+        continuation.resume("OK");
+        return COROUTINES_PACKAGE.intrinsics.IntrinsicsKt.getCOROUTINE_SUSPENDED();
+    }
+}
+
+// FILE: main.kt
+import helpers.*
+import COROUTINES_PACKAGE.*
+import COROUTINES_PACKAGE.intrinsics.*
+
+fun builder(c: suspend () -> Unit) {
+    c.startCoroutine(EmptyContinuation)
+}
+
+fun box(): String {
+    var result = "fail"
+
+    builder {
+        result = JavaClass().foo(1)
+    }
+
+    return result
+}