Add tests for case when result of tail-call suspend function returning

Unit is not Unit.
 #KT-34703 Fixed

compiler/testData/codegen/box/coroutines/tailCallOptimizations/unitFunReturnsNonUnit.kt

@@ -0,0 +1,33 @@
+// TARGET_BACKEND: JVM
+// IGNORE_BACKEND: JVM_IR
+// FULL_JDK
+// WITH_RUNTIME
+// WITH_COROUTINES
+
+import helpers.*
+import kotlin.coroutines.*
+
+var c: Continuation<*>? = null
+
+suspend fun <T> tx(lambda: () -> T): T = suspendCoroutine { c = it; lambda() }
+
+object Dummy
+
+suspend fun suspect() {
+    tx { Dummy }
+}
+
+fun builder(c: suspend () -> Unit) {
+    c.startCoroutine(EmptyContinuation)
+}
+
+fun box(): String {
+    var res: Any? = null
+    builder {
+        res = suspect()
+    }
+
+    (c as? Continuation<Dummy>)?.resume(Dummy)
+
+    return if (res != Unit) "$res" else "OK"
+}

compiler/testData/codegen/box/coroutines/tailCallOptimizations/unitFunReturnsNonUnitCallSuspend.kt

@@ -0,0 +1,36 @@
+// TARGET_BACKEND: JVM
+// IGNORE_BACKEND: JVM_IR
+// FULL_JDK
+// WITH_RUNTIME
+// WITH_REFLECT
+// WITH_COROUTINES
+
+import helpers.*
+import kotlin.coroutines.*
+import kotlin.reflect.full.callSuspend
+import kotlin.reflect.KCallable
+
+var c: Continuation<*>? = null
+
+suspend fun <T> tx(lambda: () -> T): T = suspendCoroutine { c = it; lambda() }
+
+object Dummy
+
+suspend fun suspect() {
+    tx { Dummy }
+}
+
+fun builder(c: suspend () -> Unit) {
+    c.startCoroutine(EmptyContinuation)
+}
+
+fun box(): String {
+    var res: Any? = null
+    builder {
+        res = (::suspect as KCallable<*>).callSuspend()
+    }
+
+    (c as? Continuation<Dummy>)?.resume(Dummy)
+
+    return if (res != Unit) "$res" else "OK"
+}