[clang] [Clang] Allow the value of unroll count to be zero in `#pragma GCC unroll` and `#pragma unroll` (PR #88666)

[Shilei Tian via cfe-commits]

shiltian wrote:

@alexfh @ronlieb @Endilll fix in https://github.com/llvm/llvm-project/pull/89567.

https://github.com/llvm/llvm-project/pull/88666