FIR: Fix test data after making LHS of assignment an expression

KT-54648

compiler/testData/diagnostics/tests/OverridenSetterVisibility.fir.kt

@@ -0,0 +1,29 @@
+public interface ITest {
+    public var prop : Int
+        get() = 12
+        set(value) {}
+}
+
+abstract class ATest {
+    protected open var prop2 : Int
+        get() = 13
+        set(value) {}
+}
+
+class Test: ATest(), ITest {
+    override var prop : Int
+        get() = 12
+        <!CANNOT_WEAKEN_ACCESS_PRIVILEGE!>private<!> set(value) {}
+
+    override var prop2 : Int
+        get() = 14
+        <!CANNOT_CHANGE_ACCESS_PRIVILEGE, SETTER_VISIBILITY_INCONSISTENT_WITH_PROPERTY_VISIBILITY!>internal<!> set(value) {}
+}
+
+fun main() {
+    val test = Test()
+    test.<!INVISIBLE_SETTER!>prop<!> = 12
+
+    val itest: ITest = test
+    itest.prop = 12 // No error here
+}