Add -package-name flag

De/serialize package name in module binary
Resoles rdar://103531218, rdar://103531208

lib/Serialization/ModuleFileSharedCore.h

@@ -82,6 +82,9 @@ class ModuleFileSharedCore {
   /// The module ABI name.
   StringRef ModuleABIName;
 
+  /// The name of the package this module belongs to.
+  StringRef ModulePackageName;
+
   /// \c true if this module has incremental dependency information.
   bool HasIncrementalInfo = false;