As a drive-by, the order of rounding_average_u is adjusted according to src/wasm/wasm-opcodes.h.

Bug: v8:9909
Change-Id: Ia3a2ed5869f8df8a2191afa034e0b9438de98bc5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2141654Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Zhiguo Zhou <zhiguo.zhou@intel.com>
Cr-Commit-Position: refs/heads/master@{#67104}