After https://github.com/llvm/llvm-project/pull/182297, we started generated `-gsimple-template-names` debug-info by default on macOS. The test was expecting template parameters in the error message. But with `simple-template-names` typenames would not contain template parameters (unless LLDB reconstructs them to do so). This formatter test was expecting template parameters, which would fail on macOS > 26.
Because the test is just concerned with checking that the `std::valarray` formatter works as expected (not that LLDB can retrieve typenames with/without template names), this patch relaxes the assertion.
In a follow-up we should fix up any type-name printing that would break with `simple-template-names`.
b9143faf46