Add a :print_module directive to the REPL.

This is basically the same as doing a :print_decl on every decl in the module,
except that it does not print extensions that come from other modules, and
/does/ print extensions and operators that come from this module.

Does not yet work for Clang modules or the Builtin module.

Swift SVN r7601

lib/Serialization/SerializedModuleLoader.cpp

@@ -310,3 +310,11 @@ SerializedModuleLoader::getLinkLibraries(const Module *module,
     return;
   moduleFile->getLinkLibraries(callback);
 }
+
+void SerializedModuleLoader::getDisplayDecls(const Module *module,
+                                             SmallVectorImpl<Decl*> &results) {
+  ModuleFile *moduleFile = cast<SerializedModule>(module)->File;
+  if (!moduleFile)
+    return;
+  moduleFile->getDisplayDecls(results);
+}