[ParseableInterface] Pass down the module name and import source loc

- Use the name for the cached module, so that we don't end up with a
  zillion "x86_64-XXXXXXXX.swiftmodule" files in the cache when we're
  working with architecture-specific swiftmodules.

- Diagnose if the expected name is different from the name specified
  in the swiftinterface.

- Emit all diagnostics at the location of the import, instead of
  without any location at all.

include/swift/Serialization/SerializedModuleLoader.h

@@ -52,8 +52,8 @@ protected:
                   bool &isFramework);
 
   virtual std::error_code
-  openModuleFiles(StringRef DirName, StringRef ModuleFilename,
-                  StringRef ModuleDocFilename,
+  openModuleFiles(AccessPathElem ModuleID, StringRef DirName,
+                  StringRef ModuleFilename, StringRef ModuleDocFilename,
                   std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
                   std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
                   llvm::SmallVectorImpl<char> &Scratch);
@@ -129,8 +129,8 @@ class SerializedModuleLoader : public SerializedModuleLoaderBase {
   {}
 
   std::error_code
-  openModuleFiles(StringRef DirName, StringRef ModuleFilename,
-                  StringRef ModuleDocFilename,
+  openModuleFiles(AccessPathElem ModuleID, StringRef DirName,
+                  StringRef ModuleFilename, StringRef ModuleDocFilename,
                   std::unique_ptr<llvm::MemoryBuffer> *ModuleBuffer,
                   std::unique_ptr<llvm::MemoryBuffer> *ModuleDocBuffer,
                   llvm::SmallVectorImpl<char> &Scratch) override;