[clang] [Clang] Added check for unexpanded pack in attribute [[assume]] (PR #91841)

[Azmat Yusuf via cfe-commits]

azmat-y wrote:

Would I be correct in assuming that the test would be somewhat similar to this.

llvm-project/clang/test/Sema/unroll-template-value-crash.cpp
```
// RUN: %clang_cc1 -x c++ -verify %s
// expected-no-diagnostics

template <int Unroll> void foo() {
  #pragma unroll Unroll
  for (int i = 0; i < Unroll; ++i);

  #pragma GCC unroll Unroll
  for (int i = 0; i < Unroll; ++i);
}
```
Can you point me towards information on clang_cc1 and similar arguments used for lit. I have scanned through [lit](https://llvm.org/docs/CommandGuide/lit.html#execution-options) but could not find a mention for it.


https://github.com/llvm/llvm-project/pull/91841