FIR checker: report SETTER_PROJECTED_OUT

compiler/testData/diagnostics/tests/generics/varProjection/setterProjectedOutNoPlusAssign.fir.kt

@@ -1,10 +0,0 @@
-// !DIAGNOSTICS: -UNREACHABLE_CODE
-interface Tr<T> {
-    var v: T
-}
-
-fun test(t: Tr<out String>) {
-    // resolved as t.v = t.v + null!!, where type of right operand is String,
-    // so TYPE_MISMATCH: String is not <: of Captured(out String)
-    <!ASSIGNMENT_TYPE_MISMATCH!>t.v += null!!<!>
-}