[FIR] Ignore smartcast for non-final members from Java, ^KT-50219 Fixed

compiler/testData/diagnostics/tests/smartCasts/noSmartcastForNonFinalMembersFromJava.kt

@@ -0,0 +1,21 @@
+// FIR_IDENTICAL
+// KT-50219
+
+// FILE: Base.java
+public class Base {
+    protected String field;
+    protected final String finalField = "finalFieldValue";
+}
+
+// FILE: test.kt
+class Derived : Base() {
+    fun foo() {
+        if (field == null) {
+            field.length
+        }
+
+        if (finalField == null) {
+            finalField<!UNSAFE_CALL!>.<!>length
+        }
+    }
+}