Add tests for obsolete issues

#KT-15913 Obsolete
 #KT-12248 Obsolete

compiler/testData/diagnostics/tests/modifiers/const/kt12248.kt

@@ -0,0 +1,19 @@
+// FILE: Bar.java
+
+public class Bar {
+    public static final int BAR = Foo.FOO + 1;
+}
+
+// FILE: Test.kt
+
+class Foo {
+    companion object {
+        const val FOO = 1
+    }
+}
+
+class Baz {
+    companion object {
+        const val BAZ = Bar.BAR + 1
+    }
+}