Add test for obsolete issue

The problem was fixed in d51bb2c053

 #KT-37692 Obsolete

compiler/testData/diagnostics/tests/resolve/overloadConflicts/kt37692.kt

@@ -0,0 +1,14 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+abstract class Bar<T>
+
+class Foo<T> : Bar<T>(), Comparable<Foo<*>> {
+    override fun compareTo(other: Foo<*>): Int = TODO()
+}
+
+infix fun <T : Comparable<T>, S : T?> Bar<in S>.test(t: T) { }
+infix fun <T : Comparable<T>, S : T?> Bar<in S>.test(other: Bar<in S>) {}
+
+fun checkFunctions(exp1: Foo<Int?>, exp2: Foo<Int>) {
+    exp1.test(exp2)
+}