Fix merging two reference values

In this case, make the result of value type Object instead of unknown.

compiler/testData/codegen/box/coroutines/intLikeVarSpilling/listThrowablePairInOneSlot.kt

@@ -0,0 +1,34 @@
+// WITH_RUNTIME
+// WITH_COROUTINES
+// FULL_RUNTIME
+// KJS_WITH_FULL_RUNTIME
+
+class JarFile {
+    fun entries() = listOf<String>()
+}
+
+private fun scriptTemplatesDiscoverySequence(): Sequence<String> {
+    return sequence<String> {
+        for (dep in listOf<String>()) {
+            try {
+                val jar = JarFile()
+                try {
+                    jar.entries().map { it }
+                    val (loadedDefinitions, notFoundClasses) = listOf<String>() to listOf<String>()
+                    listOf<String>().forEach {
+                        yield(it)
+                    }
+                } catch (e: Throwable) {
+                    e.message
+                }
+            } catch (e: Exception) {
+                e.message
+            }
+        }
+        yield("OK")
+    }
+}
+
+fun box(): String {
+    return scriptTemplatesDiscoverySequence().first()
+}