TEST: Tests for "null" constant added

backend.native/tests/codegen/basics/null_check.kt

@@ -0,0 +1,23 @@
+//--- Test "eqeq" -------------------------------------------------------------//
+
+fun check_eqeq(a: Any?) = a == null
+
+fun null_check_eqeq1() : Boolean {
+  return check_eqeq(Any())
+}
+
+fun null_check_eqeq2() : Boolean {
+  return check_eqeq(null)
+}
+
+//--- Test "eqeqeq" -----------------------------------------------------------//
+
+fun check_eqeqeq(a: Any?) = a === null
+
+fun null_check_eqeqeq1() : Boolean {
+  return check_eqeqeq(Any())
+}
+
+fun null_check_eqeqeq2() : Boolean {
+  return check_eqeqeq(null)
+}