[NI] Discriminate resulting type Nothing(?) at fixation stage

compiler/testData/diagnostics/tests/inference/nothingType/lambdaNothingAndExpectedType.kt

@@ -0,0 +1,12 @@
+// !LANGUAGE: +NewInference
+// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE
+
+fun <K> select2(x: K, y: K): K = TODO()
+fun <K> select3(x: K, y: K, z: K): K = TODO()
+
+fun test2(f: ((String) -> Int)?) {
+    val a0: ((Int) -> Int)? = select2({ it -> it }, null)
+    val b0: ((Nothing) -> Unit)? = select2({ it -> <!UNUSED_EXPRESSION!>it<!> }, null)
+
+    select3({ it.length }, f, null)
+}

compiler/testData/diagnostics/tests/inference/nothingType/lambdaNothingAndExpectedType.txt

@@ -0,0 +1,5 @@
+package
+
+public fun </*0*/ K> select2(/*0*/ x: K, /*1*/ y: K): K
+public fun </*0*/ K> select3(/*0*/ x: K, /*1*/ y: K, /*2*/ z: K): K
+public fun test2(/*0*/ f: ((kotlin.String) -> kotlin.Int)?): kotlin.Unit

compiler/testData/diagnostics/tests/inference/nothingType/nothingWithCallableReference.kt

@@ -22,8 +22,7 @@ fun test(f1: (Int) -> Unit, f2: kotlin.Function1<Int, Unit>) {
     dependantSelect2(null, ::foo)
     dependantSelect3(null, ::foo, ::cloneFoo)
     dependantSelect3(null, f1, ::bar)
-    // Here we have LOWER(Nothing?), UPPER(Function1) and therefore type variable is fixed to the former
-    dependantSelect3(null, <!TYPE_MISMATCH!>::bar<!>, f1)
+    dependantSelect3(null, ::bar, f1)
 
     // These errors are actually can be fixed (and, probably, should) if we force resolution of callable reference
     dependantSelect3(null, ::foo, <!TYPE_MISMATCH!>::bar<!>)