[llvm] added a script to update llvm-mc test file (PR #107246)

[Brox Chen via llvm-commits]

broxigarchen wrote:

After some research on windows platform I realized that all lit tests for the update scripts are disabled for windows platform (either binary check failed or platform not supported. In windows, llc is named llc.exe so the llc binary does not exists -_-!).

Disabled windows platform test for this script as well

https://github.com/llvm/llvm-project/pull/107246