PROTON-2820: [Ruby] Change mapping of pn_handle_t to intptr_t

This avoids the swig conversion code from raising an error when the
handle is an address that is a negative integer.

c/include/proton/cproton.i

@@ -26,10 +26,10 @@ typedef unsigned long int uint32_t;
 typedef long int int32_t;
 typedef unsigned long long int uint64_t;
 typedef long long int int64_t;
-#if UINTPTR_SIZE==8
-typedef unsigned long long int uintptr_t;
+#if INTPTR_SIZE==8
+typedef long long int intptr_t;
 #else
-typedef unsigned long int uintptr_t;
+typedef long int intptr_t;
 #endif
 
 /* Parse these interface header files to generate APIs for script languages */

ruby/cproton.i

@@ -56,7 +56,7 @@ Keep preprocessor directives and macro expansions in the normal header section.
 %}
 
 /* Treat pn_handle_t like uintptr_t - syntactically it is a C void* but really it's just an int */
-%apply uintptr_t { pn_handle_t };
+%apply intptr_t { pn_handle_t };
 
 %typemap(in) pn_bytes_t {
   if ($input == Qnil) {

ruby/lib/util/wrapper.rb

@@ -111,7 +111,7 @@ def fetch_instance(impl, attachment_method = nil)
         end
         return result
       end
-      RBCTX = self.hash.to_i
+      RBCTX = self.hash
     end
 
     # @private