[libcxx-commits] [libcxx] [libc++][ranges][enumerate_view] Update sentinel `equal` test (PR #222331)

[A. Jiang via libcxx-commits]

frederick-vs-ja wrote:

The improved parts LGTM. But have we been testing the constraints of this `operator==`?

https://github.com/llvm/llvm-project/pull/222331