The RoundFloat/RoundDouble functions should return the Canonical
NaN if the input is a NaN.

Change-Id: I19928a8a3d78770757c6fe2e240254efe9944bdc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2475493
Commit-Queue: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70530}