[FIR] Add UNCHECKED_CAST

Regenerate diagnostics code

compiler/testData/diagnostics/tests/inference/regressions/kt35844.fir.kt

@@ -11,7 +11,7 @@ class B<T> {
 fun <Y> foo(c: A<Y>): Y = TODO()
 
 fun <E> main(a: A<E>) {
-    a as A<B<*>>
+    a <!UNCHECKED_CAST!>as A<B<*>><!>
 
     foo(a).b()
 }
@@ -21,7 +21,7 @@ class AOut<out X>
 fun <Y> foo(c: AOut<Y>): Y = TODO()
 
 fun <E> mainOut(a: AOut<E>) {
-    a as AOut<B<*>>
+    a <!UNCHECKED_CAST!>as AOut<B<*>><!>
 
     foo(a).b()
 }

compiler/testData/diagnostics/tests/inference/regressions/kt38691.fir.kt

@@ -1,14 +0,0 @@
-// !LANGUAGE: +NewInference
-// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE
-
-class Inv<T>
-fun <T> materializeInv() = Inv<T>()
-fun <X> foo(x: Inv<X>, y: X) = materializeInv<X>()
-fun <X> foo(x: Inv<X>, y: () -> X) = materializeInv<X>()
-
-fun <R> main(fn: () -> R) {
-    fun bar(): R = null as R
-    val x1 = foo<R>(materializeInv()) { fn() } // OVERLOAD_RESOLUTION_AMBIGUITY only in NI
-    val x2 = foo<R>(materializeInv(), fn) // OK
-    val x3 = foo<R>(materializeInv(), ::bar) // OK
-}

compiler/testData/diagnostics/tests/inference/regressions/kt38691.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !LANGUAGE: +NewInference
 // !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE