Generate bridges for super-calls only when needed

#KT-2887 Fixed

compiler/testData/codegen/super/kt2887.kt

@@ -0,0 +1,16 @@
+open class Base<T> {
+    public open fun foo(t: T): T = t
+    
+    public open fun bar() {}
+}
+
+class Child: Base<String>() {
+    override fun foo(t: String): String {
+        return super<Base>.foo(t)
+    }
+    
+    override fun bar() {
+        super.bar()
+    }
+
+}