KT-10460: use unsubstituted descriptors

while comparing overloaded generic functions  for specificity.

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

@@ -0,0 +1,11 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER -REDUNDANT_PROJECTION
+
+class In<in T>() {
+    fun f(t : T) {}
+    fun f(t : Int) = t
+}
+
+fun test1(x: In<String>): Unit = x.f("1")
+fun test2(x: In<in String>): Unit = x.f("1")
+fun test3(x: In<<!CONFLICTING_PROJECTION!>out<!> String>): Unit = x.<!NONE_APPLICABLE!>f<!>("1")
+fun test4(x: In<*>): Unit = x.<!NONE_APPLICABLE!>f<!>("1")