kDoubleRegZero register is not hardwired to 0.0, we need to check
it's value before using it.

Change-Id: I8a64ac55294f51a9a5f96a39a3b344f7e34d508a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2479223Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn>
Cr-Commit-Position: refs/heads/master@{#70595}