Copy type parameters for JVM function accessors

Otherwise generic signature wasn't correctly written to accessors, resulting in
classfiles not being valid and javac failing to compile Java sources against
them

compiler/testData/compileJavaAgainstKotlin/method/AccessorGenericSignature.java

@@ -0,0 +1,5 @@
+package test;
+
+public class AccessorGenericSignature {
+    private final BadClass b = new BadClass();
+}