[CursorInfo] Pass primary path to allow comparing previous ASTs

Update the cursor requests to also pass in their primary file. Snapshots
should be compared using this file, not the input buffer name. This
fixes AST re-use when the AST is usable with snapshots.

Resolves rdar://110344363.

tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h

@@ -660,8 +660,9 @@ public:
                      Receiver) override;
 
   void getNameInfo(
-      StringRef Filename, unsigned Offset, NameTranslatingInfo &Input,
-      ArrayRef<const char *> Args, SourceKitCancellationToken CancellationToken,
+      StringRef PrimaryFilePath, StringRef InputBufferName, unsigned Offset,
+      NameTranslatingInfo &Input, ArrayRef<const char *> Args,
+      SourceKitCancellationToken CancellationToken,
       std::function<void(const RequestResult<NameTranslatingInfo> &)> Receiver)
       override;