[clang] [Clang][diagnostics] Fix structured binding shadows template param loc (PR #129116)

[Shafik Yaghmour via cfe-commits]

shafik wrote:

> @shafik I added the sample to our test cases, not sure if we can add source loc in expected line, I will check that

h/t @erichkeane something like this should help get us the confirmation in the test we want: https://github.com/llvm/llvm-project/pull/129116

https://github.com/llvm/llvm-project/pull/129116