Storing with E64 when SEW=32 has EMUL=2, which copies |n| 64 bit wide
data to the result double array already. Besides, accessing v1 when
EMUL=2 is reserved.

R=yahan@iscas.ac.cn

Change-Id: I0870d53c36b642529cab753409f52016d79219b8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3878442
Commit-Queue: Yahan Lu <yahan@iscas.ac.cn>
Reviewed-by: Yahan Lu <yahan@iscas.ac.cn>
Cr-Commit-Position: refs/heads/main@{#83110}