scrooge: Add maxThriftBuffer parameter for inherited services

Followup to "scrooge: Reduce allocations in generated code" (RB_ID=628710)

Problem

Thrift services that extend other services do not pass in the maxThriftBufferSize param and the StatsReceiver, so default values are used.

Solution

Add new parameters to the parent constructor.

RB_ID=639844

scrooge-generator/src/main/resources/scalagen/finagleService.scala

@@ -22,7 +22,7 @@ class {{ServiceName}}$FinagleService(
   protocolFactory: TProtocolFactory,
   stats: StatsReceiver,
   maxThriftBufferSize: Int
-) extends {{finagleServiceParent}}{{#hasParent}}(iface, protocolFactory){{/hasParent}} {
+) extends {{finagleServiceParent}}{{#hasParent}}(iface, protocolFactory, stats, maxThriftBufferSize){{/hasParent}} {
   import {{ServiceName}}._
 
   def this(