[clang] [Clang] Remove redundant check for scoped enums in shift operators (PR #152865)

[Timothy Choi via cfe-commits]

tinnamchoi wrote:

The tests to be introduced in #152698 should cover this, running them locally seems fine.

https://github.com/llvm/llvm-project/blob/45c8c060cc45cd3abfb3d4d4eda676ab6ce30890/clang/test/SemaCXX/enum-scoped.cpp#L439-L452

https://github.com/llvm/llvm-project/blob/45c8c060cc45cd3abfb3d4d4eda676ab6ce30890/clang/test/SemaCXX/enum-scoped.cpp#L580-L593

https://github.com/llvm/llvm-project/blob/45c8c060cc45cd3abfb3d4d4eda676ab6ce30890/clang/test/SemaCXX/enum-scoped.cpp#L623-L624

https://github.com/llvm/llvm-project/pull/152865