[Serialization] Remove 'EnableSameSDKCheck' it's not needed with the soft-reject

Author: xymus

include/swift/AST/SearchPathOptions.h

@@ -327,10 +327,6 @@ class SearchPathOptions {
   /// would for a non-system header.
   bool DisableModulesValidateSystemDependencies = false;
 
-  /// Enforce loading only serialized modules built with the same SDK
-  /// as the context loading it.
-  bool EnableSameSDKCheck = true;
-
   /// A set of compiled modules that may be ready to use.
   std::vector<std::string> CandidateCompiledModules;
 

lib/APIDigester/ModuleAnalyzerNodes.cpp

@@ -2419,10 +2419,6 @@ swift::ide::api::getSDKNodeRoot(SDKContext &SDKCtx,
 
   auto &Ctx = CI.getASTContext();
 
-  // Don't check if the stdlib was build with the same SDK as what is loaded
-  // here as some tests rely on using a different stdlib.
-  Ctx.SearchPathOpts.EnableSameSDKCheck = false;
-
   // Load standard library so that Clang importer can use it.
   auto *Stdlib = Ctx.getStdlibModule(/*loadIfAbsent=*/true);
   if (!Stdlib) {