Fix false positive "Null can not be a value of a non-null type"

Inferred type of receiver of orElse  is Optional<T & Any>
Generic descriptor is orElse(E!): E!
Substituted descriptor is orElse(T): T , and that is the problem.

Seems that E!  => (T & Any)!  gets expanded to just T  or T & Any , however it should be expanded to
(T & Any) .. (T & Any)?  => T & Any .. T & Any

T & Any is NotNullTypeParameter(T)

The problem is that (T & Any)?  is expanded to T & Any,
that is seems to be wrong.

 #KT-15236 Fixed

compiler/tests-java8/tests/org/jetbrains/kotlin/checkers/DiagnosticsWithJava8TestGenerated.java

@@ -48,6 +48,12 @@ public class DiagnosticsWithJava8TestGenerated extends AbstractDiagnosticsWithFu
         doTest(fileName);
     }
 
+    @TestMetadata("nullForOptionalOrElse.kt")
+    public void testNullForOptionalOrElse() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/testsWithJava8/nullForOptionalOrElse.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("samWithConsumer.kt")
     public void testSamWithConsumer() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/testsWithJava8/samWithConsumer.kt");