[llvm] [NFC][X86] Clang-format X86DisassemblerDecoderCommon.h (PR #73272)

[Shengchen Kan via llvm-commits]

KanRobert wrote:

> Some of this seems to decrease reability. The code was structure to emphasize simarlities. What was the motivation?

The motivation is the annoying warnings reported by code formatter in pre-commit testing. It keeps reminding me to format those code even if the code is not changed in my patch.  From my point, the structure helps little about the readability. (although different people may have different ideas ...), so I format the code in this separate patch to avoid the warnings 

https://github.com/llvm/llvm-project/pull/73272