[Basic] Remove getVirtualFile

This patch removes getVirtualFile because it has been deprecated for
more than 10 months since:

  commit b1aea98
  Author: Jan Svoboda <[email protected]>
  Date:   Wed Sep 25 10:36:44 2024 -0700

I'm not aware of any downstream use AFAICT.

Author: kazutakahirata

clang/include/clang/Basic/FileManager.h

@@ -237,11 +237,6 @@ class FileManager : public RefCountedBase<FileManager> {
   FileEntryRef getVirtualFileRef(StringRef Filename, off_t Size,
                                  time_t ModificationTime);
 
-  LLVM_DEPRECATED("Functions returning FileEntry are deprecated.",
-                  "getVirtualFileRef()")
-  const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
-                                  time_t ModificationTime);
-
   /// Retrieve a FileEntry that bypasses VFE, which is expected to be a virtual
   /// file entry, to access the real file.  The returned FileEntry will have
   /// the same filename as FE but a different identity and its own stat.

clang/lib/Basic/FileManager.cpp

@@ -368,11 +368,6 @@ void FileManager::trackVFSUsage(bool Active) {
   });
 }
 
-const FileEntry *FileManager::getVirtualFile(StringRef Filename, off_t Size,
-                                             time_t ModificationTime) {
-  return &getVirtualFileRef(Filename, Size, ModificationTime).getFileEntry();
-}
-
 FileEntryRef FileManager::getVirtualFileRef(StringRef Filename, off_t Size,
                                             time_t ModificationTime) {
   ++NumFileLookups;