[Modules] Avoid false swift module sharing

When the swiftmodule is built with different clang importer arguments,
they can have the same module hash, causing them to be wrongly re-used even
they contains different interfaces. Add ReducedExtraArgs to the module hash to
disambiguate them.

However, some Xcc arguments, most commonly `-D` options do not affect the
swiftmodule being generated. Do not pass `-Xcc -DARGS` to swift
interface compilation to reduce the amount of module variants in the
build.

rdar://131408266

lib/Frontend/ModuleInterfaceLoader.cpp

@@ -2072,6 +2072,8 @@ InterfaceSubContextDelegateImpl::getCacheHash(StringRef useInterfacePath,
   auto normalizedTargetTriple =
       getTargetSpecificModuleTriple(genericSubInvocation.getLangOptions().Target);
   std::string sdkBuildVersion = getSDKBuildVersion(sdkPath);
+  const auto ExtraArgs = genericSubInvocation.getClangImporterOptions()
+                             .getReducedExtraArgsForSwiftModuleDependency();
 
   llvm::hash_code H = hash_combine(
       // Start with the compiler version (which will be either tag names or
@@ -2113,6 +2115,10 @@ InterfaceSubContextDelegateImpl::getCacheHash(StringRef useInterfacePath,
       // correctly load the dependencies.
       genericSubInvocation.getCASOptions().getModuleScanningHashComponents(),
 
+      // Clang ExtraArgs that affects how clang types are imported into swift
+      // module.
+      llvm::hash_combine_range(ExtraArgs.begin(), ExtraArgs.end()),
+
       // Whether or not OSSA modules are enabled.
       //
       // If OSSA modules are enabled, we use a separate namespace of modules to