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/Frontend/Frontend.cpp

@@ -1382,6 +1382,8 @@ ModuleDecl *CompilerInstance::getMainModule() const {
       MainModule->setHasCxxInteroperability();
     if (Invocation.getLangOptions().AllowNonResilientAccess)
       MainModule->setAllowNonResilientAccess();
+    if (Invocation.getSILOptions().EnableSerializePackage)
+      MainModule->setSerializePackageEnabled();
 
     // Register the main module with the AST context.
     Context->addLoadedModule(MainModule);