Due to lack of testing environment before, there are some bugs in the
implementations of wasm-simd on mips64 platform, this CL fix them
according to the test on Loongson 3A4000.

Change-Id: I59ab6315987fc94a06cf0bf23754f5c593879532
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2162416
Commit-Queue: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn>
Reviewed-by: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67413}