Delete the clang-format Visual Studio plugin code (#108342)

This was obsoleted by Visual Studio providing built-in support for
running clang-format in VS2017.

We haven't shipped it for years (since
10d2195), never got it working with
VS2019, and never even tried with VS2022.

It's time to retire the code.

Author: zmodem

clang/tools/CMakeLists.txt

@@ -5,7 +5,6 @@ add_clang_subdirectory(driver)
 add_clang_subdirectory(apinotes-test)
 add_clang_subdirectory(clang-diff)
 add_clang_subdirectory(clang-format)
-add_clang_subdirectory(clang-format-vs)
 add_clang_subdirectory(clang-fuzzer)
 add_clang_subdirectory(clang-import-test)
 add_clang_subdirectory(clang-linker-wrapper)