Sema: Remove isExportedAs, it's no longer used and it was outdated

Author: xymus

include/swift/AST/Module.h

@@ -1087,10 +1087,6 @@ class ModuleDecl
   /// Returns the associated clang module if one exists.
   const clang::Module *findUnderlyingClangModule() const;
 
-  /// Does this module or the underlying clang module defines export_as with
-  /// a value corresponding to the \p other module?
-  bool isExportedAs(const ModuleDecl *other) const;
-
   /// Returns a generator with the components of this module's full,
   /// hierarchical name.
   ///

lib/AST/Module.cpp

@@ -2649,14 +2649,6 @@ const clang::Module *ModuleDecl::findUnderlyingClangModule() const {
   return nullptr;
 }
 
-bool ModuleDecl::isExportedAs(const ModuleDecl *other) const {
-  auto clangModule = findUnderlyingClangModule();
-  if (!clangModule)
-    return false;
-
-  return other->getRealName().str() == clangModule->ExportAsModule;
-}
-
 void ModuleDecl::collectBasicSourceFileInfo(
     llvm::function_ref<void(const BasicSourceFileInfo &)> callback) const {
   for (const FileUnit *fileUnit : getFiles()) {