During Package CMO, SIL cloning happens during which

SILOptions::EnableSerializePackage info is lost.

SILVerifier needs this info to determine whether resilience
can be bypassed for decls serialized in a resiliently
built module when Package CMO optimization enabled.

This PR adds SerializePackageEnabled bit to Module format
and uses that in SILVerifier.

Resolves rdar://126157356

lib/Serialization/ModuleFile.h

@@ -659,6 +659,11 @@ public:
     return Core->Bits.AllowNonResilientAccess;
   }
 
+  /// Whether this module was built with -experimental-package-cmo.
+  bool serializePackageEnabled() const {
+    return Core->Bits.SerializePackageEnabled;
+  }
+
   /// Whether this module is compiled with implicit dynamic.
   bool isImplicitDynamicEnabled() const {
     return Core->Bits.IsImplicitDynamicEnabled;