Enhance the function_ref instruction to maintain a refcount on the

SILFunction that it references.  Use this in the mandatory inlining
pass to remove deserialized transparent functions, to clean up the
-emit-sil output of the compiler (and presumably speed up compile 
time).  This implements rdar://15272652



Swift SVN r9699

include/swift/SIL/SILModule.h

@@ -169,6 +169,7 @@ public:
   using iterator = FunctionListType::iterator;
   using const_iterator = FunctionListType::const_iterator;
 
+  FunctionListType &getFunctionList() { return functions; }
   iterator begin() { return functions.begin(); }
   iterator end() { return functions.end(); }
   const_iterator begin() const { return functions.begin(); }