Fix primitive types mapping

Use boxed version if type was enhaced to not-nullable

compiler/testData/codegen/box/platformTypes/primitives/identityEquals.kt

@@ -3,7 +3,7 @@ fun box(): String {
     l.add(1000)
 
     val x = l[0] === 1000
-    if (!x) return "Fail: $x"
+    if (x) return "Fail: $x"
     val x1 = l[0] === 1
     if (x1) return "Fail 1: $x"
     val x2 = l[0] === l[0]

compiler/testData/codegen/boxWithJava/enhancedPrimitives/J.java

@@ -0,0 +1,7 @@
+public class J {
+    // This test checks that although type '@org.jetbrains.annotations.NotNull Integer' is perceived as simple Int,
+    // it's correctly mapped to 'Lj.l.Integer' by JVM backend
+    public static String test(@org.jetbrains.annotations.NotNull Integer x) {
+        return "OK";
+    }
+}

compiler/testData/codegen/boxWithJava/enhancedPrimitives/box.kt

@@ -0,0 +1 @@
+fun box() = J.test(1)