Add test for smart cast on a value bound to when subject variable

E.g.:
  when (val y = x?.foo()) {
    null -> ...
    else -> ... // 'x' is also non-null here
  }

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -22484,6 +22484,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                     doTest(fileName);
                 }
 
+                @TestMetadata("smartCastOnValueBoundToSubjectVariable.kt")
+                public void testSmartCastOnValueBoundToSubjectVariable() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/when/withSubjectVariable/smartCastOnValueBoundToSubjectVariable.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("smartCastsOnSubjectVariable.kt")
                 public void testSmartCastsOnSubjectVariable() throws Exception {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/when/withSubjectVariable/smartCastsOnSubjectVariable.kt");