[llvm] [TableGen] Remove redundant buffer copies for ULEB128 decode calls. (PR #80199)

[Jason Eckhardt via llvm-commits]

nvjle wrote:

If one of @jyknight or @0x59616e could review this small patch, it would be appreciated.

The Windows build check failed, but this seems to be a transient error unrelated to my change.

https://github.com/llvm/llvm-project/pull/80199