Do not write "? extends" and "? super" in immediate arguments of supertypes in Java generic signatures

compiler/testData/writeSignature/declarationSiteVariance/SuperClassWithVariance.kt

@@ -0,0 +1,7 @@
+
+open class Base<A, in B, out C>
+class Derived<A, B, C>: Base<A, B, C>()
+
+// class: Derived
+// jvm signature:     Derived
+// generic signature: <A:Ljava/lang/Object;B:Ljava/lang/Object;C:Ljava/lang/Object;>LBase<TA;TB;TC;>;